RE: KMP Corsair
Wow, with all the capital letters and bold text I'd have thought that you'd actually flown and crashed the plane to confirm that 130 mm is unflyably tail heavy. Did someone have a bad case of first flight jitters and was looking for an excuse not to fly? ;)
Posted on: 11/20/2009 3:30 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9267942

RE: GP GEE BEE
Wow, that is some amazing video! I don't think that I've ever seen an r/c video that was that harrowing, yet not also disastrous. A friend of mine had a take-off experience like that when I was trying to instruct him on how to fly his H9 Corsair. No video of that take-off, though. I told him to "baby the throttle" meaning "move the throttle slowly to avoid engine torque yanking the plane around." He interpreted my "baby the throttle" advice as "don't go above half throttle." He lifted off too quickly and got into a alternating left and right tip stall situation for a few cycles until I suggested that he advance the throttle more to gain some much needed air speed, afterwhich he was able to gain control of the Corsair without damage. I thought he was a goner several times during that take-off just like with your video. Glad that all ended well on both accounts.
Posted on: 11/17/2009 5:57 AM by Author "Craig-RCU" in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=9259661

RE: GP GEE BEE
[quote]ORIGINAL: Guerra Do any of you good folks know about a thread where someone (either unbalanced or ambitious) mounted floats on a GP Gee Bee?? [/quote] I saved a picture of a GB on floats, but I don't remember where I got it.
Posted on: 11/12/2009 12:14 AM by Author "Craig-RCU" in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=9247724

RE: H9 Corsair flaps
[quote]ORIGINAL: jtbuck [quote]ORIGINAL: Craig-RCU Thanks again John. I'm using a Super Tigre G-90 with a pits muffler turning a 14-6 2 blade Master Airscrew. The spinner is a Tru Turn 1 1/4'' hub that I got from my local hobby store. They didn't have the flanged hub in stock...;search=Go [/quote] Craig, I'll be starting on mine when I get all parts and do flaps. I haven
Posted on: 11/10/2009 9:18 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9242889

RE: Balancing a canard or tandem wing biplane for initial flight.
[quote]ORIGINAL: iron eagel I think your post #10 was fine. I just wasn't sure if you knew who was involved with SC, when you asked what word, that is all... They, as I, would agree with what you had said. [/quote] Sorry, I guess I took your tutelage of such basic information about Burt Rutan, SC and their connection to canard designs to be a sign that you don't think that I know the most basic things about canards. Maybe I took Cowboy's post the wrong way too as a criticism?
Posted on: 11/4/2009 12:29 AM by Author "Craig-RCU" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226833

RE: Balancing a canard or tandem wing biplane for initial flight.
[quote]ORIGINAL: rc bugman I don't dis-believe your explanations but somehow I am missing the logic. Thanks again Elson [/quote] I'll try again. Moving the C.G. toward the elevator produces tail heavy behavior only when the elevator is toward the tail of the airplane. It's just that simple. Moving the C.G. toward the elevator on a canard produces nose heavy behavior because the elevator is toward the nose. In all planes, moving the C.G. toward the nose produces more nose heavy behavior and moving the C.G toward the tail produces more tail heavy behavior. The location of the elevator is irrelevant to this. Your logic lead to the contradictory result that moving The C.G. toward the nose of a canard would cause it to behave as if it were tail heavy. The error in your logic is of thinking that the specific case of conventional designs applies to all cases of various airplane designs. This is an error of inductive reasoning. An example of the error is this argument. Bill is tall. Bill is a person, therefore all people are tall. Your reasoning follows that same form. In the same way it does not follow that because Bill is a tall person that all people are tall, it does not follow that moving the C.G. toward the elevator on a conventional design has the same effect on all designs. Any clearer for you?
Posted on: 11/4/2009 12:10 AM by Author "Craig-RCU" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226798

RE: Balancing a canard or tandem wing biplane for initial flight.
[quote]ORIGINAL: iron eagel [quote]ORIGINAL: Craig-RCU [quote]ORIGINAL: CowboyLifesaver I'd call Scaled Composites and get the word from the horses mouth myself. [/quote] What word? [/quote] Burt Rutan designed many canards, he should be able to explain the aerodynamics... [/quote] Yes, I figured that is what Cowboy meant. I was asking for specifics about what he thinks Burt Rutan, or anyone
Posted on: 11/3/2009 11:07 PM by Author "Craig-RCU" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226667

RE: Balancing a canard or tandem wing biplane for initial flight.
[quote]ORIGINAL: CowboyLifesaver I'd call Scaled Composites and get the word from the horses mouth myself. [/quote] What word?
Posted on: 11/3/2009 12:38 AM by Author "Craig-RCU" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9224214

RE: Balancing a canard or tandem wing biplane for initial flight.
[quote]ORIGINAL: rc bugman Thanks for the replies. Somehow the responses are not logical. Here is why. With conventional aircraft (wing in front, elevator in rear), a tail-heavy airplane puts too much authority on the elevator which makes the elevator too sensitive and the plane becomes difficult to impossible to control. Move the weight forward, the elevator loses sensitivity and the plane becomes better ''behaved''. Move the weight too far forward, and the elevator becomes insensitive and the plane becomes difficult to fly. With a canard, the plane is backward with the wing in the rear and the elevator in front. Logic would suggest that too much nose weight would make a canard difficult to control like a tail heavy conventional plane. Elevator would have too much authority. Move the weight back and the fore mounted elevator would lose authority. A tandem-wing biplane is yet another beast. Two equal sized wings located on either end of a fuse seems to be naturally stable where ever the CG is located between the wings. Elson [/quote] You have to suspect that it is your logic that is flawed when your logic leads you to reason that, on a canard, "nose heavy=tail heavy." You are making an incorrect inference that the effect of moving the weight toward the elevator of a conventional design is going to apply to all configurations. The correct relation between C.G. and elevator sensitivity has to do with the C.G.s position relative to the aerodynamic center of an aircraft not the elevator. I think part of what is confusing your logic is the names that we give to various control surfaces. Control surface names have no bearing on aerodynamic stability. We just call these different control surfaces different names out of convention more than anything else. For example, flaps on a conventional design can have the same function as the elevator on a canard: flaps go down-nose pitches up: elevator goes down on a canard-nose pitches up. You could even fly a conventional design with just flaps for pitch control without any movable elevator on the horizontal stab at all. It's the same with a canard configuration, no movable elevator on the horizontal stab. is needed. Pitch control can be had with elevons on the larger, aft wing only. We just tend to put pitch control surfaces on the wings furthest away from the C.G. for leverage reasons.
Posted on: 11/3/2009 12:11 AM by Author "Craig-RCU" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9224161

RE: The RCFW Hellcat Group Build
[quote]ORIGINAL: ram3500-RCU [quote]ORIGINAL: Tko310 i agree he 26cc might be a bit much could be entertaining though [/quote] I had a Gee Bee R2 a few years back. Flying was OK including the take off. Landing was a different story. Planes that are all engine are not fun to bring home. A detailed war bird with hours and hours of work in it would not be my first choice to experiment with in this way. But to each his own, as they say. [/quote] Yes, a 26cc on a 64" plane wouldn't be for a beginner pilot or anything. For the right pilot, the RCG 26 sure is a cheap way to turn a 19 or 20" prop, though.
Posted on: 11/2/2009 2:53 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9221830

RE: The RCFW Hellcat Group Build
[quote]ORIGINAL: Tko310 just to ad my two cents there are a number of .60 -1.20 size gas engines available on the market now at extremely resonable prices not only are they more afordable to opperate they can swing bigger scale props http://www.troybuiltmodels.com/items/RCSSV17-H.html this 17cc has got great reviews with comprobale weight http://www.troybuiltmodels.com/items/AEROVATE20R.html this is the one i will opt for watch the video Tighe OMeara [/quote] I don't know anything about it, but the RCG 26cc gasser might work too. Apparently the listed weight is wrong as the first of the reviews says the total weight of the engine, exhaust, ignition and hardware is 1297g. http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=9615&Product_Name=RCG_26cc_Gas_engine_w/_CD-Ignition_2.6HP/1.95kw
Posted on: 11/2/2009 12:04 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9221656

RE: Vought F7U Cutlass....will it fly?
http://www.rcuniverse.com/forum/m_3192753/mpage_10/key_/tm.htm I browsed through this thread after my last post and found some posts that confirm my advice in my last post. The plans are on the first page of the thread and they show the nose gear extends further below the fuse than do the main gear. This will result in a positive AoA of a couple of degrees at least. In post #233, Blade47 recommends increasing the AoA another 3 degrees by extending the nose gear 1.5". I found a reference to the "figure 9" maneuver in that thread but not a description of what caused it in the Global Cutlass plane design. A figure 9 [i]is[/i] the flight path that a tail heavy plane will follow on take-off, though, especially if one has to hold in a lot of up elevator to overcome a ground AoA that is not steep enough. In post #233, Blade47 also has a recommended C.G. marked in red, so it could be that this is forward of the plan's possibly tail-heavy C.G. recommendation. Anyway, best of luck with your maiden tomorrow.
Posted on: 11/1/2009 1:29 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9219193

RE: Vought F7U Cutlass....will it fly?
I'd recommend against negative incidence. Depending on how close the main gear are to the CG, it may be really hard to take off if you have a negative incidence set up when sitting on the ground. That swept back nose gear will bend back and compress more as speed and negative lift increase. Drag from the front wheels can cause more negative incidence when trying to take off too, especially if you are taking off from grass. If it is able to take off with the negative incidence, it will probably take a lot of elevator input. It could then suddenly pop off the runway into the air because it will be hard for the pilot to react to the sudden leap into the air and reduce elevator input before the plane is in a steep climb-out angle. This can cause speed to drop quickly and possibly cause a stall at low altitude. I'd recommend a positive incidence of at least a couple of degrees. Your plane will have to be moving at cruise speeds in order to take off with a positive 2 or 3 degrees incidence which is well above stall speed so should be plenty safe. Bending the nose gear forward might get you enough positive attitude and also minimize any compression due to wheel drag bending the gear backwards. What do the instructions recommend for AOA while on the ground?
Posted on: 10/31/2009 3:38 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9216974

RE: Vought F7U Cutlass....will it fly?
The real one was only called that because it was underpowered. I don't think that will be a problem for this model that is powered by a 46sf. I might go with a 10x5 prop instead of a 10x7 to give more static thrust for powering out of trouble quicker and to keep the top end speed down for a nervous first flight. Beautiful model, John and best of luck on the maiden flight.
Posted on: 10/30/2009 8:40 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9216312

RE: 1/7 Top Flite Spitfire or P47, which retracts
As far as I've heard, all the TF 1/7 scale warbirds fly just about equally well except for the P-40. Apparently, the P-40 has harsher tip stalling tendencies, which doesn't surprise me because I've heard that P-40s from other manufacturers have that problem too. I observed a guy at my club crash his Hangar9 P-40 from an altitude of about 50 ft when he got too slow after his engine quit. The H9 P-40 tip stalled to an inverted attitude and there wasn't enough altitude to recover. None of the other TF models have this problem as far as I've heard. When they stall, they might drop a wing to maybe a 45 degree bank but don't flip inverted.
Posted on: 10/28/2009 10:49 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9211090

RE: 1/7 Top Flite Spitfire or P47, which retracts
[quote]ORIGINAL: MANFRED P-47 will land better [/quote] Are you talking about the stall characteristics of the P-47 or the wider gear stance that gives it better ground handling? I'd have to say that the wide gear makes the P-47 a better first-time warbird than the Spitfire since the P-47 is such a great flying plane.
Posted on: 10/28/2009 6:10 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9210217

RE: 1/7 Top Flite Spitfire or P47, which retracts
[quote]ORIGINAL: GhostRider32 Nice writeup. Thanks for the comments. I've never put too much thought about weighing individual sheets like that...... [/quote] Thanks, I just enjoy the challenge of trying to optimise models to balance without nose weight. Weighing the sheeting is not 100% necessary to build a nice flying model and maybe this level of attention to detail is not for everyone. I just thought of another sheeting tip. In the TF P-47 instructions, they recommend wetting the sheeting on the razorback area because it is such a difficult place to sheet and then letting it dry some while it's pinned in place. That wasn't working for me so well and I was getting impatient at letting the sheeting air dry, so I got out my covering iron and applied high heat to the wet sheeting to boil it dry while holding it to shape in my hand. I found that I could warp the sheeting to a great degree by doing this and the iron-dried wood would hold its warped shape well enough that pinning the sheeting to the fuse framework became very easy. After a series of wetting and iron-drying attempts I found that I could shape the sheeting on this difficult to sheet area to practically be a drop on fit requiring few pins. Also the wood is completely dry at this stage and moisture is no longer a gluing issue anymore. I wish that I had also used this approach in sheeting other compound curved areas on the fuse. I could have saved myself some time and weight filling with light weight spackle to get rid of the "starved horse look" of the sheeting sagging a bit between fuse ribs. If I had used the iron-drying technique I could have warped the fuse sheeting into a compound curve that dropped in place with fewer pins needed and little stress on the sheeting to cause it to want to sag between the ribs. If anyone is going to try this, I'd recommend experimenting with some scrap sheeting first rather than sheeting that you've spent time prepping to be applied to the model.
Posted on: 10/28/2009 6:56 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9208624

RE: 1/7 Top Flite Spitfire or P47, which retracts
[quote]ORIGINAL: GhostRider32 Guys, I'm looking at building one of these and would like to know if there are mechanical retracts for these that work well. What did you guys use? I'm looking at the Lado's and will use these if necessary but would rather do mechanicals (due to Lado cost) if there are good ones available at a reasonable cost. I'm not planning on doing air at all. Links please if possible. Thanks. [/quote] I've built the 1/7 TF P-47 and installed Century Jet pneumatic retracts. The Century Jets are working well for me. My only complaint is that the instructions were rather sparse. The build of the P-47 went well for me. TF's instructions are very comprehensive and give lots of handy tips along the way. The only tip that I can think of that I'd add is about sheeting selection. I'd read that some people's P-47s were coming out tail heavy. Adding weight to the nose to fix that issue is part of the reason that these builds come out heavy overall. I felt like TF instructions should remind the builder that wood can be highly variable in density (if you are a noob to working with wood, the variability can be surprising), so the heaviest sheeting should be put toward the front of the plane. Knowing that some builds were turning out tail heavy and that wood can be highly variable in density, I weighed all the sheeting, wrote that weight on the sheeting (weighing the sheeting requires a fairly sensitive scale. I used a $33 "My Weigh MX 200" electronic scale. It is accurate to the tenth of a gram) and also balanced each piece at its mid-point to mark the heavy end. On the wings, I put the heaviest sheeting pieces toward the leading edge and put the heaviest end toward the wing root. Having the heaviest wood toward the leading edge and root makes it less likely that you'll put a finger through the sheeting when handling the assembled plane, makes the wing a less likely to fold in flight than it would have been otherwise and makes it less likely that the plane will be tail heavy. On the fuse, I also put the heavy end of the sheeting toward the nose. I put the heavier sheeting on the bottom of the fuse to protect against damage from belly landings and moving the model around by hand. I saved the very lightest sheeting for the tail surfaces, since they need to be light to avoid the model coming out tail heavy and you don't need to handle the tail surfaces to move the model around. The result of all this attention to the weight of the sheeting was that my monokote covered P-47 with a RCV91-CD for power came out nose heavy. I had to move the battery and receiver just aft of the wing and mount the elevator servo to the tail just under the horizontal stab to balance my P-47 at the aft-most recommended mark. I used a standard servo to operate the air retracts. That and the air tank are mounted just forward of the wing's trailing edge. So, it appears that even if one were to use a heavier covering material than monokote, such as fiberglass, paying attention to the weight of the sheeting should certainly minimize if not eliminate any need for nose ballast for balancing their model. As far as mechanical retracts, I have been very happy with the retracts that came installed in my World Models Zero 60. It is a very inexpensive and effective setup. The instructions for the ARF recommended a single standard servo for the operation of both gear. I have no doubt that would work as the stock gear legs are sorter than scale and the stock wheels are very light. I lengthened my gear to proper scale length with robostruts and use lager scale sized wheels that are light for their size but still heavier than the stock wheels. For those reasons, I used a standard servo to operate each gear instead of one to operate both. This has worked very well for me. At some point I might rig servo slowing with my radio or add-on electronics so that the gear operate in a more scale speed.
Posted on: 10/28/2009 4:29 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9208519

RE: 60 corsair balance question
[quote]ORIGINAL: frenchie79 Need a little help on balancing a Top Flight 1/8 scale Corsair-Manual calls for 4 1/4'' from leading edge and center? I'm assuming the center is midway on the wing from fuse to wing tip- because of it's Gull wing design. Anybody out their can verfy this-Thanks [/quote] I just took a look at the TF 1/8 Corsair instructions and it appears to me that the reference to "the center of the wing" is where you are can find the CG marking on the plans. It does not seem to indicate to me an indication of where you are supposed to mark the CG on the wing, because the sentence preceding that says to mark the CG location on the top of the wing on either side of the fuselage. I don't have the TF Corsair but I have the Hangar 9 Corsair which has almost the exact same measurements and CG requirements. I balanced my H9 Corsair by marking the recommended CG (4 1/4" from the leading edge of the wing in your case) at the top, root of the wings right next to the fuselage. That worked well for me.
Posted on: 10/16/2009 10:21 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9179344

RE: topflite spitfire retracts
[quote]ORIGINAL: GaryBarry HI all I have just purchased the topflite spitfire mk 9. I see that it requires modification of the retract hinge so that the cylinder is coming from the other side. Is this possible to do with mechanicals? I would prefer mechanicals due to the lower cost. Thanks Gareth [/quote] Mechanicals can be operated from the other side without modification by turning the control horn of the retract pushrod to the side or top (depending on what's convenient) and then bending the pushrod from the retract servo to reach around to the retract's control horn. On the Spitfire, the servo pushrods of such a reversed, mechanical setup look to intersect forward of the wing spar at the center of the wing. That is possibly where the retract servo could be mounted if you make some small holes in the spar webbing for the push rods to pass through. If that won't work because of the wing dihedral angle, two retract servos can be used instead (I use a single HS-75 retract servo http://www3.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=retract+servo&search=Go in my H-9 Corsair and Corsairs have more wing bend issues than a Spitfire, so I'm guessing that a single servo will work on a Spit too). Looking at the pictures in rustypep's post, it appears that if two servos are used they could be mounted aft of the spar or maybe even side by side in front of the spar at the center of the wing where a single retract servo would be mounted. If you use two servos for the retracts, you'll only need servos with half the torque of the HS-75 (92oz/in). I've had good luck using standard servos (42oz/in) on my World Models Zero60. Also, the HS-75 costs about $30, while two standard servos cost roughly half of that. I did find a standard servo that has 47oz/in of torque but I've never tried these servos myself. http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXTJJ7&P=7 Hope this helps.
Posted on: 10/15/2009 9:16 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9176632

RE: Gauging interest, Hellcat group build
[quote]ORIGINAL: Chad Veich If anyone knows where to get 3 3/4'' or 4'' wheels with a thin cross section I would LOVE to hear about them! I'm using a 3 1/2'' Robart as shown in the pics and, as you can see, they look a bit small. Scale would be 4'' and I have a pair of 3 3/4'' Robarts but they are simply too ''fat'' to fit in the wing when retracted. If you look at the full size airplane you will see it has a pretty skinny tire and now I know why! They need to be no thicker than 1'' and less would be even better. Any and all input much appreciated. [/quote] I had the same problem when searching for wheels for my H9 Corsair, all 3" plus diameter wheels are too thick at about 1-1/8". The only exeption I've found are Dave Brown treaded lite wheels which are 7/8" thick. http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB929&P=SM The largest size they make of these is 3-1/2", though. I bought the 3-1/4" and 3-1/2" wheels for my WM Zero 60 and H9 Corsair respectively. They must shrink some from the mold because their actual measurements were 3" and 3-1/4", but they are nice and narrow and light and cheap. Also, they are foam, so they don't look as scale as Robart wheels. I took apart one of my Robart wheels that I used to have on my Corsair to see if the hub could be narrowed and compress the tires narrower too. That might be possible if you cut the inner flanges off and superglue or silicone glue the tire to the hub to keep it in place and maintain the air seal. Maybe other brands would be easier to make narrower? http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD783&P=ML http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD797&P=7
Posted on: 9/23/2009 7:16 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9118805

RE: Gauging interest, Hellcat group build
Yes, the TF Corsair was the first model that I was aware that used the technique. I haven't built the TF Corsair myself, but I borrowed the technique when I bashed some flaps onto my H9 Corsair. I had my doubts that it would be able to create a slop-free link between the flaps that wouldn't bind, but it has worked very well for me so far.
Posted on: 9/19/2009 3:36 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9108034

RE: Gauging interest, Hellcat group build
[quote]ORIGINAL: Chad Veich Craig & lightning, Thanks for the compliments, much appreciated. Craig, I have the original magazine with the article you linked to in your post above regarding the Hellcat flaps and have read it many times. I was going to do the scale flaps on a Byron Hellcat kit that I had many years ago but sold it off without ever building it. I had the opportunity to see Jim
Posted on: 9/19/2009 5:32 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9107304

RE: Gauging interest, Hellcat group build
This thread has got me going with an insatiable urge to glue some balsa bits together at right angles. :) I may have to give into that urge and build a Hellcat too. How's that for non-committal? :) My "thing" is a fascination with flaps and the effects that different types of flaps have on flight characteristics, so if I build this Hellcat, I'm going to add some flaps and take the challenge upon myself to make them as scale as possible, because the Hellcat has such a unique set of flaps among warbirds. If anyone else is up to that challenge, I found a pretty good article on how to build the Hellcat's flaps. It even shows how to actuate the little flap-fairing on the bottom of the wing. http://www.mnbigbirds.com/Adobe%20Files/Grumman%20Lynx/Hellcat%20Flaps%20Article.pdf
Posted on: 9/17/2009 1:44 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9103333

RE: Gauging interest, Hellcat group build
[quote]ORIGINAL: Chad Veich Craig, Pushing the firewall back 1/2'' would be no issue at all and, in fact, I am planning on it for the kit version. That way the guys wanting to use the larger four strokes can do so without having to do any cutting. The engine mount provides plenty of length for moving the smaller powerplants forward. Speaking of TF, maybe I can sell them the Hellcat
Posted on: 9/13/2009 3:55 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9092334

RE: Gauging interest, Hellcat group build
[quote]ORIGINAL: EJWash1 [quote]ORIGINAL: Chad Veich It would definitely be out of the .60 size range and would probably end up somewhere around 14-18 pounds depending on the level of detail and finish. Just right for a 1.08-1.60 size two stroke, 1.50-2.20 four stroke, or 26-38cc gasser.[/quote] And a pretty good increase economically. The cowling would conceal an inverted .91 4-stroke... EJWash [/quote] ... And most of an OS 120 sIII. I think this overlay of the 120 on Chad's Hellcat cowl drawing is accurate to within 1/2%. The 116 measure is in mm. If this is correct, the carb is going to either need to have a cut out in the firewall to be totally enclosed in the cowl, or there will need to be an additional small hole in the cowl if the carb is flipped 180 degrees. Flipping of the carb would be unnecessary if the firewall was 1/2' or so further aft. I don't know how much of a problem it would be to move this design's firewall back that 1/2" at this point. This is a very minor problem that wouldn't affect the majority of the builders of this kit (only those installing an engine larger than an OS 91).
Posted on: 9/13/2009 3:12 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9091253

RE: Gauging interest, Hellcat group build
FWIW, the single HS-75 retract servo that I use on my H9 Corsair offers 92 oz of torque for the pair of gear, or 46 oz for each gear at a cost of $30. Standard servos can be had for under $8 a piece and offer 42-47oz torque http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXTJJ7&P=7 So, that would be a cost savings of $14 over the single retract servo with a weight penalty of about 1.5 oz. Additionally, with two standard servos, no bell-cranks would be needed (reducing the overall mechanical resistance in the system, thus needing less torque to operate) and the servos can be slowed for scale retract speeds. I have been using two standard servos for the retracts on my World Models Zero 60 with no problems.
Posted on: 9/13/2009 1:30 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9091129

RE: Gauging interest, Hellcat group build
[quote]ORIGINAL: Chad Veich Thanks for the info Craig. That may be an option for someone willing to make the necessary changes. How have your gear held up in the H9 Corsair? I flew a H9 P-40 some years back and the gear seemed to work alright though they were definitely a bit ''wobbly''. I would probably only recommend the use of the H9 gear for folks who plan to keep
Posted on: 9/13/2009 12:03 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9090945

RE: Gauging interest, Hellcat group build
Neat Hellcat project, Chad. For the extreme budget conscious builder, Hanger 9 Hellcat or Corsair gear should work. I have these gear on my H9 Corsair. I also added some 3/8" struts that I bought at VQ Models. They seem to be very close copies of Robostruts and are/were about half the price of Robostruts. They don't appear to be available right now. I don't know if they will be available again. http://www.horizonhobby.com/Products/Default.aspx?ProdID=HAN4084 http://www.vqwarbirds.com/access.html From the pictures of your unsheeted Hellcat wing on the first page of this thread, it looks like gear mount rails could be moved to the top of the wing fairly easily to accommodate the H9 gear. The H9 gear (1-3/8" wide) is about 3/8" narrower than the Robart 615s (1-3/4" wide), so wider gear rails would be needed along with moving them to the top of the wing. The H9 gear with a $30 HS-75 retract servo and bell-cranks would be about $60 dollars all together, plus $7 for H9 Hellcat/Corsair wheels.
Posted on: 9/12/2009 4:48 AM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9088886

RE: Pulse Jet 'Test Type'
The closest plane that I'm aware of is the Swedish, Saab 21 which came in both pusher and jet versions. It doesn't look like either used a counter rotating propeller or pulse jet type jet engine. The only pulse jet powered craft of WWII that I'm aware of was the V1 buzz bomb of which there were manned and unmanned versions. http://www.canit.se/~griffon/aviation/text/21saab.htm
Posted on: 8/25/2009 7:44 PM by Author "Craig-RCU" in the forum "RC Warbirds and Warplanes"
http://www.rcuniverse.com/forum/fb.asp?m=9044785