|
RE: ASM F-7F Tigercat
Brad, I ordered the struts from Tower Hobbies. They were ROBO Straight RoboStrut 1/2". Part Number ROBQ1950. These have a higher resistance to sideways deflection than the ASM units. As I have posted earlier, Tiger #3 will be sporting ESM gear. David
Posted on: 9/3/2012 3:42 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11215366
RE: ASM F-7F Tigercat
Hi Brad. I just used the actual struts and adapted them where necessary to fit the ASM mechanism. I will try to delve back into my records to see if I can find the part numbers. David
Posted on: 9/3/2012 3:19 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11215352
RE: ASM F-7F Tigercat
Hi Guys. I'm still here following the thread although I still have not got around to finishing Tiger Cat #3. On the subject of the U/C I described the trouble I had way back in my first contribution to the thread, Page 18. As I said then I had the same trouble with my ASM Invader. The Tiger Cats's U/C is just about identical. I fixed it by dropping in Robart struts. From what I understand we had best not hold our breath waiting for a re-launch of the model.[:o]
Posted on: 9/3/2012 2:17 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11215331
RE: ASM F-7F Tigercat
Good luck with the new Tigercat Brad. I haven't had a chance to touch mine since my last post. Other things on my plate. Also the recent untimely death of a very close cousin has put things into perspective. Regarding batteries, I was using a lipo with a UBEC until I was introduced to A123 2300 mAh batteries and now use them exclusively. My decals also did not stick so I made new ones using sign-writing vinyl. They stick like ...... you know the rest.[:)] The new Tiger will also sport new lettering to replace the shabby effort on the rear fuselage.
Posted on: 3/22/2012 2:26 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=11010285
RE: ASM F-7F Tigercat
Thanks guys. Just the encouragement needed to push on. Bad luck with the your plane Staggerflyer. Guess we are none of us immune from lack of motive power.[;)] Best of luck with your build Brad. Don't rush it mate. David
Posted on: 2/2/2012 11:48 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10941392
RE: ASM F-7F Tigercat
Hi Guys. Still here and currently (slowly) putting together Tigercat #3. #2 went in because of an undetected probable engine outage and a turn procedure into the dead engine. The aircraft was some distance from me at the time, around 250 meters, which made it difficult to see what the problem was. Regarding the gear doors, it has been my experience (2 Tigercats, 2 ASM Invaders) that the opening of the main doors is initiated by the descending wheel and then by the inherent spring action of the wire The force of air when flying certainly would help. I could hold the models upside down (on the ground) and the doors would still spring open. Not much has to be removed from the door edges to overcome the curvature between the intended hinge points of the doors and is hardly noticeable. Back to Tigercat #3. All of the fuselage strengthening done for #2 and has been incorporated. A full depth dihedral brace has been added at the front of the existing 'main spar' and the center glassed with 100mm cloth just to be sure. The photo shows the incision made in the undersurface to archive this, The stabilizer mounting has been considerably stiffened by installing a balsa in-fill between the longerons and a fillet between the longerons and the outer plastic skin. This fillet was achieved by smoothing in bicarbonate of soda (Baking Powder) and then soaking it with CA. This results in a rock hard fillet. The stab was then slid into place and tilted against the plastic so that epoxy could be 'poured' into the resulting gap between the balsa fillet and the stab lower surface. Once the epoxy had set the top of the stab was then fixed to the plastic skin before the fin was installed. Tip: If you haven't used the bi-carb/CA mixture before keep your head away when it 'goes off'! I invested in a Stanley Fat Max cross hair laser level which in invaluable in getting things squared up. A more ambitious modification I am currently working on is re-hinging and re-shaping the flaps so that a gap of around 5mm is left when they are extended. In addition the inner 160mm portion of the ailerons has been converted to flaps which replicates the set-up of the full size aircraft (and the ESM model). This should make landings more comfortable. It involves a lot of work and hopefully it will be worth the effort! With thanks to Rocketman's lead, landing gear intended for the ESM Tigercat has been installed. This gives me an acceptable ground clearance for the 16x8x2 props I will be using and appears to be more substantial and smoother in operation than the ASM gear. In the process, all of the gear bearers were replaced with decent and lighter Aussie hardwood. Yes Staggerflyer, the original bearers are made from rubbish wood and were not that difficult to remove once cut in half. The replacements were made wider, filling in the gap left by the originals. By the way Staggerflyer, I did try the 14x9x3 Master Airscrew props used on your electrics but found that while the max revs achieved were very close to your electrics there was not the same pull that the 16x8x2 APC props delivered. Co-incidentally, it was that flight that proved to be the demise of #2. Finally, on a lighter note, I have found out more about the manufacture of the Tigercat. It transpires, I am told, that Mr ASM is a wealthy Chinese business man who has an interest in model aircraft. He has set up his own factory with all the necessary laser cutting and plastic moulding equipment and has a private sealed airstrip near the Hong Kong Chinese border. He has become bored with the Tigercat style of model and is venturing into large electric ducted fan models. This is not, however his prime source of income. No, his day job is the manufacture of swim suits! When one looks a the structure of a Bikini the construction of his model aircraft becomes more explainable. David
Posted on: 2/1/2012 2:25 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10938032
RE: ASM F-7F Tigercat
Hey Guys, here is something to drool over. I wish![;)] http://www.vogelsangaeroscale.com/scalewingstigercat.html The color scheme is notable.
Posted on: 9/28/2011 3:21 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10739037
RE: ASM F-7F Tigercat
[quote]ORIGINAL: ausfester Does anyone have any pics of the fuz strengthening that they have done? Thanks guys [/quote] Mine are to be found in Post 426 Page 18. There are others earlier than mine. David
Posted on: 9/28/2011 6:16 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10738174
RE: ASM F-7F Tigercat
Hi RickAvery. There have been a few suggestions on this thread as to how to tame the steering cables. If I may 'push my own barrow' I would suggest you use plastic tubes as outlined in my Post #426 Page #18. I have been using this method on a few models with great success. I like the look of those dummy radials. Any more details? David
Posted on: 9/27/2011 3:07 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10737165
RE: ASM F-7F Tigercat
OK, time to out myself. [:)] Despite the known shortcomings of the ASM Tigercat, I could not resist the temptation to buy one of the last remaining kits in Australia at $275. It will be in storage until I have reason to assemble it. I am obviously also rather taken with this aircraft. I have only just last weekend had the opportunity to fly the repaired Tigercat. The take off and landing were rather inglorious but the rest of the flight was OK despite the extra weight. I have now fitted Great Planes 24oz tanks which are easily accommodated within the nacelles, replacing the 16oz DuBro's. To overcome the problem of having the tank outlet higher than the carbies ( the Lasers are inverted which puts the carbies at the bottom ) I have also fitted Perry VP-30 Regulating pumps to ensure a constant flow of fuel to the engines. These are activated by crankcase pressure and have been adjusted to give a maximum flow. A 'T' in the fuel line just before the carburetor diverts unused fuel back to the tanks. Because the existing crankcase vent on the Lasers must be open to air, another T is used just before the pump with the 90 degree portion vented back to the atmosphere. They work really well. The bigger tanks will now give me a 10 minute flight with plenty in reserve. I don't know about the rest of you but I find that 10 minutes is about as much fun as I can handle at any one time. I will post photos later. I am currently starting to assemble the TopFlight Cessna 310 kit I bought some two years ago. One thing I am considering (will be) doing with the Cessna kit is to fill the wing with foam. Apparently this model also has a 'problem' with the wing construction and filling it with expanding foam strengthens it no end. The following link points to a relevant post in the Cessna thread. http://www.rcuniverse.com/forum/m_5002875/mpage_110/key_/tm.htm Photos in post 2727 I am exploring the possibility of also doing this with the Tigercat (#3) wing center section and would be interested in getting your collective feedback. I have plenty of time to think about this. I am hoping to be flying Tigercat #2 for a while yet. David
Posted on: 9/27/2011 4:34 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10736129
RE: ASM F-7F Tigercat
Hi Guys. Was talking to a fellow club member today who happens to be the warehouse manager at Model Engines, the Australian Distributors of ASM products. It appears that there a no more Tigercat kits left over here or at the factory and we have seen the end of ASM's foray into similar type aircraft. I don't know the full details but ASM will be concentrating on Electrics in the future. So enjoy your Tigercat will you can. [;)]
Posted on: 9/25/2011 2:06 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10732870
RE: ASM F-7F Tigercat
[quote]ORIGINAL: Staggerflyer I think you'll be fine with ALL the fuselage fixes. Those seem to be the most common. I think the wing center section break was a rare one, as no one else has had the problem, yet. I think you'll be happy with the OSs. We got one radar speed check on my electric powered TCat. Got a reading of 86mph. Problem with getting a reading on it, is that all the radar ''sees'' is the props, and if the plane is not pointed directly at the gun, there is no return for the gun to read. I need to get my Eagle Tree MPH sensor mounted, so I can get a true reading. [/quote] Staggerflyer, that's an interesting result you got with the speed gun. You have previously stated that you get 9921rpm from your Rimfires with the 14x9x3 props. Carousel43 has suggested that speed is a direct relationship between propeller pitch and rpm. Using the formula ((Pitch * RPM) * minutes per hour) / inches per mile) or ((9*9921)*60)/63360) I get 84.55mph! Pretty close to your speed gun reading. I have wondered how much the efficiency of propellers should be factored into the calculated speed. Perhaps Carousel43 might give us his thoughts on this. As for the mods to the airframe ausfester, I would join Staggerflyer in recommending that you at least do ALL the fuselage strengthening described in previous posts. If you choose to also add a dihedral brace, you will find it easier if you do it through the bottom of the wing using a bit of key-hole surgery. You would only need to remove the covering in the immediate area. Take care to not interfere with the carbon fiber tube at the back of the spar. Adding a glass fiber bandage around the join between the two wing halves need only necessitate removal of the covering immediately affected. No need to do the whole wing as I did. I am certainly no expert where glass fibre is concerned. It's not that difficult really. For your information the main spar is 100mm or 4 inches back from the leading edge. I used a 4 inch wide bandage in an attempt to keep it inside the fuselage. Hope this helps.
Posted on: 9/22/2011 3:11 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10728498
RE: ASM F-7F Tigercat
[quote]ORIGINAL: Brad330l [quote]ORIGINAL: drob Hmmm. To each his own I guess.[;)] Well, I have completed the covering of the complete wing and reinstalled all the gear. Am waiting for some larger tanks before I balance. As expected the weight has gone up, 10.6kg (from 9.6kg). I think I will really need those Lasers now. David [/quote] I will always prefer ours drob[;)] Brad [/quote] My '
Posted on: 9/14/2011 3:48 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10716817
RE: ASM F-7F Tigercat
Hmmm. To each his own I guess.[;)] Well, I have completed the covering of the complete wing and reinstalled all the gear. Am waiting for some larger tanks before I balance. As expected the weight has gone up, 10.6kg (from 9.6kg). I think I will really need those Lasers now. David
Posted on: 9/13/2011 1:12 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10714079
RE: ASM F-7F Tigercat
Make that http://www.gmac.org.au/ [:)][:)]
Posted on: 9/8/2011 3:17 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10706791
RE: ASM F-7F Tigercat
Make that gmac.org.au [:)]
Posted on: 9/8/2011 1:30 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10706790
RE: ASM F-7F Tigercat
Glassing the whole center section sounds like a good idea to me, Brad. Here is something to consider with your rebuild which ever way you go. I was faced with the dilemma of trying to remove the ABS wing fairings before recovering or leaving them on and covering around them. I found that I had done too good a job installing them so left them on. Instead of covering around them however, I am extending the covering over the fillets. I have already done the outer panels as you will see. I first feathered the ABS into the balsa sheeting and took the covering right around to the 'intake'. For the center section I am feathering and also using micro sphere filler to give, I hope, an even better look. One thing to watch is to not apply too much heat to the ABS plastic with covering iron....it tends to soften as I found. Gets over the problem of fuel seeping into the wing somewhat. I have four oil cooler fillets fitted, two are from Tigercat #1 which I did not bother to fit. Your stress test should give some degree of comfort to others. I have done a similar test with mine which seems to be rock solid. Hardly surprising! My repairs are now completed except for the final covering which I will do tomorrow. If it is any consolation to you all, the glue used in the wing seems to be much better that that used elsewhere in the airframe. That is, where it touches! See last photo. David (Visit www.gmac.org.au)
Posted on: 9/8/2011 1:25 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10706789
RE: ASM F-7F Tigercat
Interesting figures there. Here is something else that I think all of you will find interesting. At the end of the WIKIPEDIA entry for the Tigercat there is a link to the Pilots Handbook for the Navy version of the aircraft. It contains good detail on the cockpit amongst other points of interest, with page 27 listing the permissible maneuvers, unladen. Loop, Immelman Turn, Aileron Roll, Wing-Over, Chandelle and Vertical Turn. It goes on to say that spins intentionally induced are not permitted.[:)] Also the maximum level speed is stated as 460mph. When this is appropriately scaled down we get 61mph! Pretty close to Carosel43 's calculations for Brad's and my models. It makes for interesting reading. To save you searching here is the link. http://www.scribd.com/doc/53345349/1949-AN-01-85FA-1-Pilot-s-Handbook-for-Navy-Model-F7F-1N-F7F-2N-F7F-3-F7F-3N-F7F-4N-Airplanes David
Posted on: 9/6/2011 3:18 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10704620
RE: ASM F-7F Tigercat
Me again. Something that might be useful to you Brad and others. Page 5 of the instructions says where to position the Flap control horns, left and right. Seems they got it back to front. If you want to make use of the ply inserts to secure the horns, the RIGHT WING panel horn needs to be approx. 140mm from the root end and the LEFT WING horn 160mm from the root end. As you can see here, I followed directions (for once) and missed. Staggerflyer, I have just noticed your response. My Laser 150 4strokes were turning around 8900rpm on the ground at max throttle with the 15x8x3 props. The 16x8x2 props give around 8500rpm. Both figures are within the 8000-9500 'useful' rev range for these motors. I think I will stay with the APC 16x8x2 props thanks. David
Posted on: 9/3/2011 10:01 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10700413
RE: ASM F-7F Tigercat
To my mind extra power does not necessarily equate to higher speeds. Is a model that cannot execute a smooth wide loop overpowered? Is a model that does not encourage big wide barrel rolls or half Cubans overpowered? I think not. Such was the case with my model with the 15x8x3 Master Airscrew props. I don't use the extra power to scream around the sky. Speed is so low on my list of priorities as to be non-existent. The ability to emulate the flight envelope of the aircraft upon which a model is based and to execute maneuvers with a smooth transition from one to the next is much more satisfying. That's what mean by exciting. The take-off for that last flight was achieved with less than 3/4 throttle and with a purposely shallow climb out. Most of the flight was done with this throttle setting or less with near full throttle used on the upwards segment of the wide loops and half Cubans. I have just viewed again the video posted by Staggerflyer (Post 399/P16). Mine did not seem to be as fast as Staggerflyer's appeared to be flying but the authority in the maneuvers was comparable. The pulling power available with the ASP 2 blade 16x8 props over the 15x8x3 props was very evident. Three blades look terrific for a static display but in my experience cannot match the performance of 2 blades. A point that seems to be overlooked here is that the carbon fiber tube in my model's wing, the same as those 3mm tubes used in the fuselage, did not do, rather was not capable of doing its job. It seems obvious to me that the designed purpose of the tube is to handle the down load on the wing center section. It is glued to the bottom of the outer ribs and the top of the center rib and to the intervening ribs where it touches. I'm no expert here but that set up would resist a down load on the wing. Negative G?? How much emphasis do I need to put on the fact that in my wing (and hopefully no others) what should been one carbon fiber tube was two. The left tube extends to around 30mm into the right wing. The tubes are joined at this point with a wire insert which itself is glued only to the continuing tube in the right wing. In effect the load that was intended to be taken by what should have been the one continuous tube relied upon the one spot of glue either side of the center rib. I have no doubt that no effort would have been made to prepare the surface of the carbon fiber to accept a positive adhesion given the poor quality of assembly in the airframe overall. It gave way leaving all the load to be taken by the lower half of the equally questionable quality 3-ply 'spar' which snapped downwards. Some pertinent facts are called for here. Brad's model with OS 75 AX 2 strokes weighed 19.4 lbs. Rocketman's model with OS 120 AX 2-strokes weighs 18.7 lbs. Staggerflyer's model with its Rimfire 120 electrics and 4x 5000ma 4 cells weighs 21.25 lbs. Mine with Laser 150 4-strokes weighs 21.16 lbs. The total weight of my model at take off would of course be higher than that of Staggerflyer's model, but the weight would obviously reduce during the flight as fuel is consumed. Staggerflyer's flight envelope appears to match that of mine. Consider the following. Laser 150 - 900 grams (31.7oz) Full Dubro 16 fluid ounce tank - 430 gms (15 oz) approx Total 1330 grams or 47 ounces Rimfire 120 - 400 grams (14oz) Two 5000ma 4 cell batteries - 1200 grams (42oz) approx Total 1600 grams or 56 ounces I believe my figures are close to correct here. The point is that Staggerflyer's model has more weight in the nacelles than mine with those [b]BIG HEAVY Lasers[/b]. The Tower Hobbies site states the power output of the OS 120's in Rocketman's Tiger to be 3.1 hp @ 9000 rpm I don't know the power output of the Laser 150 but I do know that the Laser web site clearly states 'Always use the LASER-150 if a 120 is called for'. I am guessing that Rocketman's OS 1.20 AX 2 strokes would be delivering more power than my Laser 150 4 strokes. The Lasers with higher torque, indicated by the bigger recommended props, would probably have more pull. The factory recommend props for Staggerflyer's Rimfire 120's is 16x6 to 17x6. Laser recommends 16x8 props for the 150. Staggerflyer uses 14x9x3 props. My model could not come close to Staggerflyer's model with the 15x8x3 props I was using. Go figure! Was excess power the cause of wing failure on my model? I don't believe so. Was the inherent weakness of the faulty carbon fiber wing reinforcing in my model exacerbated by the weight of the Lasers? Possibly. Or was it just an accident waiting to happen. Would we be having this discussion had my wing not failed? Probably not. We all would probably still be blissfully ignorant of the abysmal construction of the ASM Tiger Cat wing. After my last post I had already decided to additionally add a reinforcing dihedral brace to the existing spar extending it to the first ribs out from the center rib. I will replace the fillets and add others where I can after this is installed. Knowing what I now do, if, [b]IF[/b] I were to be starting a new model I would first be stripping the crappy covering from the wings (and elsewhere), at least install a dihedral brace, fuel proof the exposed balsa (I am now using diluted PVA wood glue for this purpose) and recovering with good quality material. I will be using Oracover Corsair Blue. Power? I still like the big Lasers with their great throaty 4-stroke sound.. $285 for a new kit is tempting. This is my solution to my problem. I am not dictating what others should do. It is your choice. It could well be that what I am doing is over kill but I know that I will be able to fly 'Steve Hinton style' with a reasonable degree of confidence as a result, something I am eagerly looking forward to. Have a great day guys. [;)] [;)] David
Posted on: 9/3/2011 7:10 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10700215
RE: ASM F-7F Tigercat
Work In Progress Thought I would let you see the repair prior to fixing the carbon fiber tube. I may not bother with the as yet 'empty' ribs. I would say that once the epoxy sets the wing will be substantially stronger than before. Getting the tube in was a bit of a squeeze. Anything larger than the 16mm tube I used would be much more difficult. Tip: If you intend to do the same, measure for the length of the tube at the bottom of the ribs, not the top. I cut mine just over 2mm shorter to allow me to slip in the 2mm birch ply plates. I am using 2 of the end plates at each end of the tube and one either side of the center rib. I should have fixed these before adding the fillets. You will see some staining around the nacelle fillet caused by fuel seeping under the fillet. Something I will be addressing before recovering. As an aside, I was at one of the hobby shops I frequent this morning and was told that the Tiger Cat is currently on special. Just over half what I paid for #2 at AUS$285. How does that make you feel Brad? Seems Model Engines, the Australian Importer/Distributor is trying to clear their stock. David
Posted on: 9/1/2011 11:50 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10697911
RE: ASM F-7F Tigercat
Sorry Staggerflyer fo the Staggerwing thing.[:)]
Posted on: 9/1/2011 3:34 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10697309
RE: ASM F-7F Tigercat
Staggerwing, as I said in my first post, #1 went in on the second flight. Bring a gluten for punishment I immediately purchased #2. #1 continues to be useful as you can see! [:)] In answer to other posts, yes I readily agree that the extra weight of the Laser 150's could have contributed but then I didn't anticipate that the wing structure to which they are attached would be so badly constructed. As to the extra power, the Laser factory recommends a 150 when a 120 is called for. Why use them? I know they are very reliable. They don't stop until told to is my experience, which is a useful trait where twins are concerned. I have a theory that manufactures deliberately understate the required engine size(s) for their wares. The Australian distributor for ASM products Model Engines (who incidentally, were involved to some extent in the development of the Tiger), used OS 110 Alphas in their model. I feel the extra power allows the aircraft to be flown excitingly 'scale like' and not boringly scale like as I do my Cessna 310, which now has the Laser 70's used originally in my Invader. After my experience with the ASM A26 Invader (gone to dust) and my more recent experience with the Tiger Cat, I doubt very much that I would even contemplate another ASM product. I agree, it really is a case of you get what you pay for. It has been suggested to me by fellow club members that perhaps the ASM B17 or Lancaster might be my next model. [b]NO THANKYOU!!![/b] If Tiger #2 meets an untimely demise (just don't think about it David) I would consider the PrecisionCutKits version as a replacement. I would then know exactly what I am dealing with. The Tiger Cat is a beautiful aircraft. I put it up with the Spitfire for looks. David
Posted on: 9/1/2011 3:31 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10697303
RE: ASM F-7F Tigercat
One thing I had meant to mention. On further examination of the wing I found that the 'spar' does in fact continue through the center rib. It is slotted from the top to half way down to accommodate the slotted ribs. You will see from this photo that it a snapped at the bottom. David
Posted on: 9/1/2011 4:37 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10696418
RE: ASM F-7F Tigercat
Woops! where did the pics go? I forgot to click the OK.
Posted on: 9/1/2011 4:09 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10696400
RE: ASM F-7F Tigercat
Hi guys. Here are some more pics. I removed the top sheeting from the Tiger #1 wing so I (we) could see what was underneath. I too try to fly scale like. My Nitro Cessna 310 is capable of loops and rolls but I choose not to do these maneuvers as they are out of character for the 310. I have downloaded the Steve Hinton video and often go back to it to work out a matching routine. My one indiscretion on that last flight with the Tiger was the Cuban Eight. I was enjoying the new capabilities of the Tiger with the 2 blade props so much I thought I would try a Cuban. I won't do that one again! But the others are so satisfying. When I analyze the flight, it was at the end of the Cuban that I believe the wing failed. I thought I had lost the Tiger at that point. Once I managed to get it back on an even keel it behaved normally. The landing gave no indication of any abnormality. Fortunately it was possibly the smoothest I had managed so far! I guess that the upwards pressure on the left wing held it in the correct position. It was when the weight was taken off the wheels that the wing dropped. The weak point (in the already weak wing structure) was the carbon fiber 3mm tube which on the Tiger #1 wing transverses the entire center section. On the Tiger #2 wing however, two tubes had been installed, joined by a wire insert as the first photo shows. Had the wire been glued into both tubes this reprehensible action may have gone unnoticed. It would seem that it is on this one measly carbon fiber tube that the strength of the wing mainly relies. Unbelievable isn't it?! I wonder how many other wings have a similar 'fix'. As indicated in the other photos, I plan to insert a carbon fiber tube (16mm diam, 1mm wall) that will extend out to the third last rib on either side. I have removed a section of the top sheeting equal to the width of a sheet of balsa to gain access. This will be replaced with one sheet that will extend out to the second last ribs. I also plan to add a glass fiber bandage around the join in the wing halves. I may also consider a second, shorter tube towards the trailing edge. Please feel free to comment. David
Posted on: 9/1/2011 4:04 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10696398
RE: ASM F-7F Tigercat
Hi Guys. Here is something to give you a warm and fuzzy feeling whilst throwing your Tiger around the sky with gay abandon. After two normal relaxed flights this morning with the Master Airscrew 15x8 3blades (cut down from 16x8) I decided to try it with ASP 16x8 2 blades. The difference was fantastic. I now have no doubt as to the superior efficiency of decent 2 blade props verses passable 3 blades. I was now able to confidently do nice wide loops, axial rolls, barrel rolls, half Cuban eights that I was not really game to try before. Really great fun. After landing I decided to charge up the RX battery before another fun fly. You can probably imagine my shock when I removed the fuselage top to see a gaping slit across the entire center section if the wing. I did notice an odd exit from the full Cuban eight I did just prior to landing. I had assumed, as you all probably do, that there is a nice strong continuous main spar in the wing. Wrong! As you will see from the photos, there are two 'flimsy' spars up front that are butt-jointed to the central rib with a length of carbon fibre rod to give lateral support. The rear section relies solely on the tenuous glue joint of the balsa sheeting to the central rib. I say tenuous because on my wing there is a 1mm gap between the two sides of the sheeting with filler to fill the gap, top and bottom! The left wing was being largely retained by the dowel at the front and 4mm bolt at the back. The carbon rod had apparently separated from the right wing. There was no cracking on the underside. When I contemplated what could have been I was grateful that I had gotten off so lightly. I'm not yet sure how to fix it but will probably try to wangle in a decent spar and wrap glass fibre around the center section. Another option which I am seriously considering is to build a new, strong, center section. I don't think I could confidently fly they way I want with a 'fix' to the existing wing. I will have to sleep on that. I was intending to recover the wing anyway to replace the cheap covering. The ease at which I was able to remove the original covering was testament to the quality. Oracover Corsair Blue seems to be a good match against the painted fuselage. By the way, the extra length in the nose strut along with Rocketman's suggested packing (post 439) gives adequate ground clearance for the 16 inch props. I now have an extra 25 mm length overall in the nose strut. Have a nice day guys.[;)]
Posted on: 8/31/2011 3:38 AM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10694664
RE: ASM F-7F Tigercat
After the heavy landing I wrote about earlier, a distinct hesitancy in the steering was traced to the fact that the steel pin had bent. I had my brother turn up a replacement from 'good' steel to which I applied a film of grease (automotive axle grease) before installation, partly to stop the possible seepage of lock-tite when I screwed in the grub screws. I also smeared the other moving parts of the mechanism with the same grease. This has resulted in a very smooth operation all round. By the way, my landings are getting better![:)]
Posted on: 8/27/2011 2:48 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10689641
RE: ASM F-7F Tigercat
Hi Elojim I used temporary packers to ensure that the gear went in straight. There is probably no real benefit in making these permanent. The downside is that it would be more difficult to remove/install the retract with a permanent fix. David
Posted on: 8/18/2011 3:49 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10676608
RE: ASM F-7F Tigercat
Thanks Rocketman. Age is a state of mind. I plan to live forever...so far so good!
Posted on: 8/13/2011 2:12 PM by Author "drob"
in the forum "Twin & Multi Engine RC Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=10669062
| 
