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Twin Engine trainer - 8/18/2003 10:10:58 AM   
Cessna26



Posts: 430
Joined: 6/15/2003
From: Salt Lake City, UT, USA
Status: offline 		Does anyone know of a good twin engine trainer that is gas or glow. I would like the build a b-26 maybe soon and would like to find out about a twin engine trainer. It would be my first multiple engine plane.


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T. Buhler
Cessna26
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Twin Engine trainer - 8/18/2003 1:43:07 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Cessna26:

Look here:

http://www.rcuniverse.com/forum/tm.asp?m=989022

and

http://www.rcuniverse.com/forum/tm.asp?m=1011897

The first, the Twin-Air 45 is my preference, the Morris plane is a lot more responsive, andthereforw I don'tthink it's as good as a trainer.

Bill..

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Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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Twin Trainers - 8/18/2003 5:33:26 PM   
twinman



Posts: 1628
Joined: 1/19/2002
From: Katy, TX, USA
Status: offline 		Look down the posts and there are various posts on Bashing a plane into a twin.
Wish the manufacturers would listen to this type of cry for help.

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Twin Engine trainer - 8/18/2003 9:51:06 PM   
toucano


 

Posts: 212
Joined: 4/2/2002
From: city, USA
Status: offline 		Twinman,

I suspect the GP group got burned on the Twinstar and are gun shy to produce another twin ARF.

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Twin Engine trainer - 8/18/2003 10:08:20 PM   
IWC


 

Posts: 155
Joined: 6/3/2003
From: washinton, MI, USA
Status: offline 		[url]www.ne-aero.com[/url]

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Twin Engine trainer - 8/18/2003 10:17:55 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		All:

I don't think Great Planes got "Burned," but I suspect they thought there would be a greater sales volume than they got.

Joe Average is, and probably will remain, afraid of twins, so the market for them will always be a small percentage of the total.

With my Super Duellist project we were able to sell 50 kits, at a cost not much more than the wood alone would have cost at your LHS. There were a few more requests later, but when an offer of ten more was made I got only two firm orders. And for just two kits I couldn't hold the price, so they were not filled.

If you compare RC planes to cars, the twin market penetration would then be the sports and exotic cars. And if RC planes were as common as cars the market share for twins would be large enough to interest the larger kit/ARF companies. Consider the sales volume for the Chevrolet Corvette. And even with the sales it has, GM has come close to dropping the Corvette several times.

Just something to think about.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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twins - 8/19/2003 2:48:26 AM   
twinman



Posts: 1628
Joined: 1/19/2002
From: Katy, TX, USA
Status: offline 		Bill,
Could not have said it better.
It is our hope that this forum will increase the interest in Mulit's and hopefully avoid some of the expensive learning processes that others, (ME) have had, through answering questions on these really fantastic planes in our hobby.
You can have all the neat single engine fighters at the field you want....take off with a twin, triple, four engine.......or ...uh more and note the attention.......never let them see you sweat!!!

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Twin Engine trainer - 8/19/2003 3:10:10 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Well, let's see here. I have six K&B 40s not committed to planes... Nah. Not enough.

Wow!! Look what I just found in this box! Eleven K&B 61 engines...

But the SIZE it would have to be...

Anyone want to bankroll such a project?

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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11 K&B's - 8/19/2003 4:34:12 AM   
twinman



Posts: 1628
Joined: 1/19/2002
From: Katy, TX, USA
Status: offline 		Bill,
There are some pretty sweet deals on large biplanes in the For sale area........
How about one on the center of the fuse, six on the top wing, and four on the bottom wing. Please do not pick the type bipe with the lower wing recessed behind the upper.
Send pictures........Uh,,checked the lose change,,,,,uh tapped out after the last 10' twin.
Send us some pictures though.

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RE: Twin Engine trainer - 9/11/2003 3:54:14 AM   
sabrejet


 

Posts: 32
Joined: 9/9/2003
From: Colorado Springs, CO, USA
Status: offline 		I uused to have the hobbico twinstar, but it crashed when the left engine went out. So I took the parts off of it and stuck it on the Hobbico Avistar. Now I have a high wing twin, running two O.S. LA 46's. It's fast and it can still fly like high speed trainer. The high wing makes it a little more stable than the Hobbico twinstar.

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RE: Twin Engine trainer - 9/22/2003 4:44:53 AM   
Russo247


 

Posts: 2
Joined: 9/21/2003
From: Bala Cynwyd, PA, USA
Status: offline 		Several web sites provide product reviews for the Hobbico Twinstar. RCM and MAN have long articles. All say the plane took off fast, climbed well, performed all aerobatics, flew very stable, wings level in stalls and slowed down well for landings. I suspect the latter is the result of super-draggy nacelles. Some complained about small fuel tanks and 6 minute flights. One warned that engines larger than .32s, especially ball bearing .40s, will make it go so fast that the stab can be cracked during a pull-up. Fuel storage for .40s would also be a problem.
I am trying to avoid the engine-out problem by modifying the whole kit with a YS53 mounted inside the cabin, buggy-type cog belts running inside the wings to drive counter rotating props, smooth nacelles with ball bearing aluminum shafts, cheek air scoops made from wheel pants, removable belly air scoop which doubles as hot air dump and encloses the muffler at the rear, additional aspirator hot air dump at rear fuselage bottom, cabin rear windows (4) cut out and repositioned to dump hot air, cabin top/windows removable as a 17" long hatch, starter system made from a Jacobs chuck, wing roots located at the fuselage sides and secured in 6 places, aluminum dihedral brace reaching out to the 3rd rib on both sides, cored-out ribs forward of the spars made of 1/2" ply, large under-wing hatches for access to the drives. These changes add about 3" to the wingspan and widen the wheel track. A few items still remaining but hope to be in the air soon. Members of 3 clubs are waiting to see it fly.

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RE: Twin Engine trainer - 9/22/2003 6:37:14 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Russ:

You will definitely have done a complete elimination of having offset thrust due to engine failure. But you will also have brought needless complication and complexity to replace it.

Have you checked to see how much power you will lose in the belt drives? How about the prop shafts running in greased or dry bearings? How long will they last at 10K rpm?

And how about... Never mind. Either you've done the engineering or you haven't.

I'll just point out that remote props have been tried many times, and abandoned every time. Wilbur and Orville had remote props driven from a central engine. And a modern development that could have used remote engines did not - the YF-22 Osprey - because of the transmission losses.

If yu've ever wondered why a helicopter's transmission gets so hot, it's those same losses.

I do not say it wont work, I just say there are better, and proven, ways to do it.

Bill, the naysayer (For the moment)


_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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RE: Twin Engine trainer - 9/22/2003 7:39:50 AM   
Russo247


 

Posts: 2
Joined: 9/21/2003
From: Bala Cynwyd, PA, USA
Status: offline 		Please note that the prop shafts run on lubricated ball bearings. These are flanged, Conrad type, angular contact bearings made by Barden. They will be operating nowhere near their DN rating. If they fail, they will be replaced with router ball bearings. The cog belts and drive pulleys are the the same equipment that drives 6 lb. buggies at 60 MPH across parking lots and race tracks. The engine to prop shaft ratio is 6 to 5; 6 engine revolutions produce 5 prop revolutions. It is more fun to try this than it is to scrap the idea and put in two mundane .25s.

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RE: Twin Engine trainer - 9/22/2003 9:54:15 AM   
Flyboy Dave



Posts: 13514
Joined: 3/20/2002
From: San Bernardino County, CA, USA
Status: offline 		Russo247....

....I don't mean to sway you from your plan, Sir....but wouldn't small nuclear reactor, with a couple steam powered generators
running some H.D. electric motors work just as well on the
trainer...? You could do away with those troublesome belts,
as well as the fancy bearings and such.... ....of course you
could still use the rear window, and fuselage cooler/vents
to keep the fuselage from melting down.

I do agree....the modified/streamlined nacelles would be
beneficial with the trainer format....just for the acceleration,
and top speed alone....and also the .25 glow engines would
be mundane....at best.

Why don't you try this....alot of the Fellas (including mysefl)
have found the answer to the "mundane problem" by adding
more power to the model....in the way of a couple of .40
sized engines. What a concept....they fit right into the existing
mounts as well. The vertical performance goes right up to
the "outstanding" range....but you might find that a complete flight at a full throttle setting....might be a bit more than you
had in mind.

If you really wanted to blow the covering off the Twin Star
trainer....you could substitute a couple of these old fashioned
OS .40 FSR engines to the apparatus....but I don't think it
would last too long....

....never mind....

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A mechanic says..."Oh yeah, watch this".
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RE: Twin Engine trainer - 9/23/2003 6:07:50 AM   
Touchdown


 

Posts: 47
Joined: 2/4/2003
From: Perth, AUSTRALIA
Status: offline 		Hey Russ,

Don't listen to the naysayers. Sounds like a cool project to me and I'd love to see pictures of the finished aircraft and any flights you do.



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RE: Twin Engine trainer - 10/2/2003 8:22:09 AM   
MR Flyer57



Posts: 528
Joined: 7/23/2002
From: Elko, NV, USA
Status: offline
Your project is ambitious and very interesting. If you get moving on it, or if you already have made progress, please post a few pics.
I have a new twinstar kit sitting on my bench, just looking for a chance to fly. I have been stalling because .25s are a dog and .40s eat too much gas and won't be in the air very long. Because I know that a dead engine might be the last mistake that I make with it, I have cooled my jets for now. I have thought about making a pony tank in the center of the wing or in the fuse. Any ideas that might help?
MR Flyer57

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