RE: Torque tubes on ailerons/flaps?
Charles, Have you settled on about 8 degrees down thrust for the turbine/exhaust pipe? Which turbine are you going with?
Posted on: 9/1/2009 11:31 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=9061584

RE: Dreamworks New Products Announcement - Including Nano!
Todd, For some of us who scratch build (looking for trailing link gear for 12-16 lt turbine class aircraft), what are the approximate top of strut to axel lengths for the mains & NG for the boomerang Nano? What wheel sizes can fit?
Posted on: 8/6/2009 5:45 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8995764

RE: Mibo A-10 arrives!!
Was seaching for pictures, need more! Congratulations Ron & Sean. I've got to see that.
Posted on: 7/16/2009 11:48 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8938245

RE: Favorite Jet Wheel! The Cadaillac of choice?
Charles, For the sake of weight, in a '44 sized aircraft, or 12-14 lb thrust turbine powered, plane where all up weight less than 14 lbs or so is desired, I would go with plastic hubs-Robart scale wheels with Tam's brakes, or perhaps Robart's version of the Compact unibrake if they now have them in stock. Most other wheel/brake combinations are much heavier (Glennis, Intairco, BVM) with solid tires made for hard surfaced runways with higher braking forces. Your choice may depend somewhat on that type of surface you will be flying from. For the C101, trailing link struts might look good, check the small ones by Altercare. An electric retract system usually weighs more than a simple air system-either air up spring down, or air both ways, with a Jetronics valve. Electric driven mechanicals require two servos-one for the NG, one for the two mains. Not sure of the weight of the LADO system. Maybe you could research that and report comparisons of weight here.
Posted on: 7/13/2009 2:10 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8929347

RE: Can any jet be Turbo'ed?
Thank you for the link, Enrique. I estimate that C-101 had a span of 63 inches (1.60 m), powered by a P-80. Can you tell us what was the final dry takeoff weight, after turbine installation and painting? Has it flown yet? Cheers
Posted on: 6/26/2009 3:05 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8883293

RE: Can any jet be Turbo'ed?
Charles, You will have better success with the lighter aircraft. I have flaps, struts, air retracts, brakes and sullivan wheels, 7 servos in all (5 HS85 MG, 2 HS225MGs), all in a chrome monokoted sabre (JHH FG fuse, balsa built up wing) weighing in at less than 8 lbs dry. About 1/2 it's 300 flights have been with 8 lb thrust Green '44, TO weight about 9.5 lbs. No problems flying off well cut grass, TO roll about 2-250 ft. Yes the Gold gives it unlimited performance, but my Gold is now going back into the Cougar, which drops its wet weight down closer to 12.5 lbs, and it takes off with authority. You don't often fly at full thrust like in the old DF days, usually 60% for tooling arround, full thrust going up for nice big 300 ft loops, etc. Higher thrust/weight is neat but in a small jet, your jet can disappear from flyable sight in less than 5 sec at full throttle! Yes, I would go with the spars, and you need a canopy hatch on top large enough to see the turbine during starts (you will need access to a hand shut off valve and for C02 for the inevitable hot start someday), even if your major access is via the bottom/wing opening . For the sake of weight, I would leave the resin and cloth just to high stress areas, and primarily cover it with monokote. LADOs I believe are much heavier than an air system, too heavy for this sized aircraft. Why don't we continue discussing this by email. I would be happy to help with suggestions and you should probably also bounce these ideas off other turbine flyers in your local area. Some swear by Jetcats, some love Wrens. I think a '54 in your C101would be just too much. I love doing odd birds and conversions. Current project- my '54 is going into an old T2 Buckeye-span 66 weight about 13.5 dry! lturner3@gmail.com Milwaukee Electrons Fond du Lac Aeromodelers
Posted on: 6/25/2009 2:01 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8880192

RE: Can any jet be Turbo'ed?
Charles, I would join the wing cores conventionally, 2 in wide FG tape. Add some spanwise CF tow top and bottom on the sheeting, and glass the center section with 2 oz cloth perhaps 10 inches out each side from center. Leave the wings long for now, you can always clip the tips off later to more 'scale-like'. The bigger engines require more kero, higher wing loading. A p60 in a Fox Sabre, span 55, requires 70 oz fuel aboard for ave 5 min duration flights with 20% margin, weighs in at almost 14 lbs dry. My Cougar with 14 lb thrust MW54 burned 50 oz out of a total of 70 for 6 min flights, weighed 15 lbs dry. Why not a 10 lb thrust 'Gold' 44 in a 10 lb aircraft with adequate wing area? I get 8 minutes pleasant flying burning only 32 oz kero in my 'Gold' Sabre, almost 300 flights now. Cheers
Posted on: 6/24/2009 11:02 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8876957

RE: Can any jet be Turbo'ed?
Ok Charles, I have two pipes. 1st in the Sabre, made by Larry Wolfe. The Bell Mouth lip dia measures 2.687 inches. It necks down to 2.062 about 0.5 aft of the bell inlet. The inner pipe runs like a diverging cone over about 7.5 inches, from 2.062 out to 2.375 inch 7.5 inches aft where it joins the straight part which runs another 12 inches to the outlet, also 2.375 inch dia. This pipe is doubled most of its length, from about 3 inches aft of the lip all the way back to extend about .375 inch further aftwards than the inner pipe. Overall length 20 in. The overlap of the outer pipe 3/8ths beyond the inner pipe uses the high velocity turbine exhaust to pull cooling air between the outer and inner pipes. The second pipe for a JHH Cougar was made by Wren and obtained from Ron Ballard of Wrenturbinesusa.com. It has the same bell, neck, and diverging cone aftwards about 7.5 inches, and a shorter straight part, measuring about 3.75 long, overall length about 12 inches. The aft outlet diameter is again 2.375 inches. Only the aft 2 inches is doubled: a little out of round maybe 2.7 vertically and 2.5 horizontally. Again the outer pipe protrudes 3/8 to 1/2 inch beyond the inner pipe. Considering your C-101 is nearly straight winged, your turbine will probably sit with its compressor 3 to 4 inches forwards from the Trailing edge, assuming you put all battery weight up forwards. You can set you cg at 25% MAC and slide the turbine&pipe backwards until it balances. I use Hitech analog servos throughout (no digitals) putting all servos up front with Nyrods running to rudder & elevator horns. With the big cheek cowl intakes, you could put two saddle tanks (8 to 12 ozs) each side laterally about mid wing, and drain them into a central 16 -24 oz tank with felt clunk between the intakes just in front of the turbine starter motor. 40 oz Fuel load close to the cg. The Gold 44 with starter/FOD, mount, F&G solonoids, pump, ECU & Lipo weighs about 33 oz. 40 Oz kero weighs about 34 oz- dry tanks another 10-12 oz. Power system dry weight maybe 55 oz . Now add weights of servos/Rx/Rx bat, and Retracts, struts and wheels, Air system, maybe another 24 oz. With the airframe about 5 lbs, comes to about 10lbs dry, 12 lbs wet, with nominal max thrust about 10 lbs. Could be do-able. I would go for it, but 1st fly a trainer type to get ready for it. Cheers
Posted on: 6/23/2009 6:45 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8875070

RE: Can any jet be Turbo'ed?
Charles, I would also vote for the Wren Gold '44 turbine, a true 'gem' producing an actual 10 or more lbs of thrust. I fly the Jet Hangar Sabre with a Gold, span about 54 inches (with my own built up wing, perhaps 1.75 inch thick at the root with cord about 13 inches), dry weight about 8 lbs, carrys 40 fluid oz kero, getting 8 min flights while consuming about 32 oz. A bit of FG and Carbon fiber tow reinforcement-maybe the middle third of the joined wing, also the fuselage-tail feather joints, spring air retracts like those for the Savex L-39. Monokote for a light covering. If you can keep it down to 8-9 lbs dry, it could have good wing loading and thrust to weight ratio, maybe, with luck, good flying characteristics. The main hang up I see is your requirement for a tail exhaust opening of 2.06 inches. The standard Wren diverging exhaust pipes have a double wall about the last 2 inches from the aft end, with outer diameter about 2.75 inches. You might get away with a 2.125 inch diameter straight single walled exhaust pipe if it were double wrapped with ceramic blanket, but it might burn the balsa in the back. Maybe you could move the fuse exhaust opening forwards 1-2 inches and let the pipe extend out that distance. I wouldn't give up on your favorite old C-101 project, but start learning about turbines on a flyable trainer type. You want something conventional you can quickly build up and fly without the 'harriness' of an untried aircraft. Something like the Jet Mach for the Gold '44. Shoulder wing, similar area, easily accesible turbine just aft of the wing. Good luck and keep talking up your project.
Posted on: 6/23/2009 1:00 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8873233

RE: Turbine Waiver - IA, IL, or WI
IflyEm35: Check out www.fdlaa.com. A bit of a ways from Sun Prarie, but our field is the best in Wisconsin. Turbines are flown most every weekend. DE, the club president is a turbine CD and you can check with him.
Posted on: 5/21/2009 5:24 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8788194

RE: A123 Battery/Regulator Questions
Cactusflyer, To clarify, is the older '54 Mk II Wren you are powering with A123s a Manual start or Auto Start? The currents passing through the FADEC are likely much higher and more critical with autostart- ECU+Glow plug+solonoids +Starter motor, putting the electronics at risk, while manual start with an external glow, battery&switch should lessen the tendancy to fry the FADEC. Pehaps we should float these questions with Gaspar, the designer of the Wren FADECs. He is often very helpful.
Posted on: 5/4/2009 11:03 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8739348

RE: To Bypass or Not To Bypass???
Not sure why, but the larger turbine installations often do not take advantage of the extra 5-10% thrust available by using a diverging tailpipe. These are sold by Wren for their smaller turbines and were studied by John Wright, I believe, in an article in RCJI a number of years ago. They work at least in part on a venturi principle, using the high speed turbine exhaust gasses to suction additional air (mass flow) from the fuse out a bell-mouthed tailpipe. Probably wouldn't work with a fully 'bypassed' installation or if there is significant restriction of inlet air. If your aim for an installation was to improve take off and low speed or high alpha performance, as in a single piped Eurosport, you might get better thrust with lighter weight using a divergent tailpipe without any bypass system. Has anyone out ther tried this?
Posted on: 4/3/2009 11:53 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8644922

RE: New sub-forums for the Jets Forum
I agree that the most useful possible sub-forum might be a Jet specific 'Wanted' posting area. It need not have all the data/pictures etc in the classifieds and a post could refer to a specific classified ad if necessary. Everything else, including the occasional full scale and other/off topic threads/posts are often entertaining and do not need any change in the way the threads are handled.
Posted on: 3/30/2009 12:36 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8631246

RE: OS46 DF Engine Trouble....
I second the motion: get rid of the pumps. As I understand it, the oscillating piston with flap valves in the pumps are unable to keep up with the high vibrational frequency of .45 DF engines turning 22-23k. You are going to have a problem with a DF A10 and any fuel system (single or separate tanks) with main tanks located down near the wing and the cg: could be 4-6 inches lower than the carburators/venturis. Reminds me of my 45 DF Sabre with its tank mounted low-actually in the wing root center section. It will forever be difficult to consistently get the right amount of carb suction & pipe pressure. The amount of exhaust pressure transmitted to the tanks will depend greatly on the rpm and what type of exhaust system you are using. Are you using a standard exhaust mufflers, or some type of short (Weston) tuned pipe? You might consider moving the tanks higher and more aftwards in the fuse to reduce the gravity gradient as well as the length of the fuel tubing runs. You could test that on the ground by seeing if external tanks mounted as high in the fuse as they could be possibly installed give you more consistent engine runs. If that helps, then reinstall the tanks high and aftwards in the fuse and balance the A10 with full tanks (using nose weight/battery packs, etc) and an aftwards as possible CG. As fuel burns off it should become more nose heavy.
Posted on: 3/30/2009 9:59 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8630786

RE: Turbine Tax credit
How about Microturbines for electricity generation? 1) Could our model sized turbines be adapted to generate electricity spinning a magnet in a coil? Maybe we could ge a grant to 'stimulate 'that. 2) Would our turbines run on Biodiesel or ethanol? Or perhaps, at night, could they be run on hydrogen/oxygen accumulated from solar cell powered electrolysis? Maybe we should be encouraging Wren to get into the power generating business!
Posted on: 3/12/2009 2:57 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8570723

RE: New JetMach Sport 60 build
You might consider the type of home-made hinged FOD screen built by sidgates, that can be flipped out of the way for a hand held wand starter. There are pictures in post #7 of the 12/18/08 thread 'Wren Users' by author aquaskimen.
Posted on: 2/19/2009 1:39 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8494971

RE: congrats to woody aka pantherman
Nice classic Navy. Congrats Pantherman, petera38. How do you guys attach/detach the tip tanks, or are they permanent. I have a conversion of another classic underway, a old D&B Buckeye kit for my Wren '54.
Posted on: 1/13/2009 12:04 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8353476

RE: Multiplex Funjet with a turbine
Spiderjets, So I guess you would recommend an eagar beaver son with good eyes and Binocs for the Kolibri, Yes? Grandchildren OK?
Posted on: 11/25/2008 11:43 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8181654

RE: Best windows desktop picture (jets only)
This one works for me.
Posted on: 11/4/2008 10:19 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=8114238

RE: Oakdale Aircraft F-35 construction
Accurate 3 view planforms and especially cross sections of the F-35 may not be available yet. The F-35B has been modified quite a bit from the X-35B. Some drawings and details can be found at http://www.codeonemagazine.com/archives/2008/articles/apr_08/f35transition/index.html For the F35-B, there are major changes in the main and aux inlets for the fan, added ventral inboard Weapon bays, a different canopy and altered nose gear doors. The engine inlets/nacells have been 'shortened' 30 inches and changed to 3 sided (from 4 on the X series). The span is increased (33 to 35 feet), the fuse longer (9 inches) without nose boom and maybe a little fatter with a more horizontal look over the engine in the side view. The horizontal tails are slightly larger but shortened in span, and the vertical tails are taller but with increased sweep and less cant angle. All difficult to guess at for any F-35 model. Russ Ahlberg at www.Oakdaleaircraft.com may be able to help you with scalable cross sections for the X-35B. I find good pictures at http://www.f-16.net/f-16_forum_viewforum-f-22.html
Posted on: 9/17/2008 11:53 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7963333

RE: F-35 Lightning II scale1:6
Thanks so much, Fritz. Wow, that balance point is essentially at the forwards wing/fuse junction. What a dart. My best guess would have put the cg 10-15% further aft, way too tail heavy! Cheers
Posted on: 9/15/2008 6:21 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7957409

RE: F-35 Lightning II scale1:6
Fritz, For the rest of us scratch builders, could you post the Length & Span of your X35B, and the location of the 'dry' balance point of your model relative to the nose? Even better, if you are able, perhaps you could indicate the location of the cg on the top planform view as in Post #6 by Pat Fernandez. Would be a great help to me on a smaller version for the Wren '44. Thanks so much.
Posted on: 9/15/2008 9:03 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7955881

RE: F-35 Lightning II scale1:6
Congratulations Fritz, And don't apologize for the pics: there is no better picture of a maiden flight than a perfect landing! PM me with some rough specs and cg location, if possible. Great job.
Posted on: 9/11/2008 9:24 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7942929

RE: F-35 Lightning II scale1:6
Go, Fritz, go. Keep us informed about your first flight. Could you repeat your model's specifications, Length, Span, weight, and tanks empty balance point or 'cg' relative to some fixed point, such as distance back from the nose or back from the wing/fuse junction, so we may learn about its balance & flight characteristics for our own scratch built models. All we have so far is quesses about the best cg. Will keep our fingers crossed for you. Good luck!
Posted on: 9/5/2008 10:49 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7922591

RE: JHI f-86 FJ-2 who has one and i need some help.
MIke, What is the fuel tank set up of the FJ-2? How many fluid oz each for the center and the saddle tanks? (For my built up F86 wing, I use a 16 oz boat 'V' tank cross ways in front of the spars, just aft of a single flap servo, plus a centered 24 oz tank in front of my Green '44' turbine). Thanks,
Posted on: 9/2/2008 11:16 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7911650

RE: Felt Clunk problems?
Thanks so much for the Pics, John. You use about a 1/8th inch inner tube, and Tygan to run to the bottle stopper? Looks about the same size as the Wren type felt clunk, and you certainly can't beat the price!
Posted on: 8/5/2008 11:50 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7811224

RE: Felt Clunk problems?
Unfortunately, a full UAT weighs in at almost 7 oz weight, nearly 1/2 lb which on a '44 sized aircraft is really excessive. Wish someone would make something similar with fittings for 3 mm fuel tubing, a normal sullivan type gas plug and about 2 fluid oz volume. I have 200 or so flights on a JHH Sabre with a Green '44 using the Wren type felt clunk, without a flame out attributable to bubbles. I know Larry W has gone to using a lighter weight 'bubble trap' fashioned out of a little 4 fluid oz sullivan tank, but there still remains the undesirable added weight of about 4 oz or so. I think I would maybe add a 2nd washer to the felt clunk, to compress the felt a little bit better, soak it in kero and shake it around a bit while pulling fuel through it to see if those tiny bubbles might not disappear. Make sure you have a large enough vent on the tank, perhaps 5/32nds brass, facing forwards to get a little ram air pressure. Works for me. Cheers,
Posted on: 8/4/2008 9:51 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7806562

RE: Wrens new engine
A footnote, everybody: The 1st factory produced kit-build turbine in it's class (33 lb/ 15kg thrust), only the 2nd after the hightly successful MW 54 Mk3 kit. Now the 'other' manufacturers, with Wren's expertise at illustrating and simplifying assembly and the right kit price, are really going to feel the competition. Congratulations to a first class company! Come on Sara, we need a name for it!
Posted on: 7/14/2008 1:02 PM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7729536

RE: Wren Turbine Open day
Sara, Wish I could come from the states. Is Ron going to have 'Open Days' and will you send him some 'cakes' to distribute? What exactly is the Mk 4 kit: the latest revision of the '54 kit (14lbs), or (hint) a preliminary kit of the Super Sport (17-19lbs)?
Posted on: 7/11/2008 11:53 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7718890

RE: JHH A7.....all up weight?
Perry, A lighter configuration of the RAM 500 can be obtained by converting to manual starts using a Wren Eco FADEC. The heavy RAM ECU battery can be replaced by a standard 4 oz 4 cell 1100 ma Nicad to power the original fuel pump via the FADEC. I get up to 4 flights of my FACET on one charge this way. The old ECU battery is used off-board for starting by connecting to the original starter motor through a manual switch for 'blipping' up the rpm, then disconnected. I use external propane and a 2 V glow battery to get it to 'pop' at the right time. The only new components you would need, except for changing some wiring connectors, would be the FADEC with display, a 4 wire Hall sensor to go under the hood, one of the Wren temp probes and their manual switch. Takes about a pound of accessory weight out of the aircraft. Manual starts of the 500 are easy and actually fun. Be glad to help if your are interested. Cheers,
Posted on: 6/24/2008 11:08 AM by Author "L Turner" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=7655070