PDA

View Full Version : Large Twins


Big Oakden
01-07-2006, 01:17 AM
Anyone out there completed a large twin yet?
(Other than the Cessna 336/337)?

Am Curious to know how many have tackled this issue, as I am about to.

Thanks,

Dave

phat23
01-07-2006, 01:42 AM
I'm flying a 62" twin that started life as a World Models Sky Raider Mach I. It now sports a new foam wing with 2 Endo's geared 3.0:1 and MAS 9x6 props. Power is from 10 cell GP3300's.

BradT
01-07-2006, 03:35 AM
Dave, how large is "large" to you? My twins have ranged from a 48" S400 sports model, to a 74" warbird, with a few sizes in between. All of them have been brushed motors, and almost all with round cells, as they were built or converted before BL and li-pos were available, or affordable.

Already built/flown:

Falcon E-Plane 48" span, 2xS400, 10x1400AA cells

Hobbico Twinstar ARF conversion 55", 2xMag Mayhem, 20xRC2000 cells

Mosquito 74", 2xTrinity Ruby 16T, 20x2600Nimh

Beaufighter 65", 2xTrinity Ruby 16T, 20x2600Nimh

Partenavia 80", 2xMag Mayhem, 10xRC2000, tested several other motor/cell systems, in series and parallel.

Sonic Liner 48"? Delta foamie, 2xS400, 8x2600Nimh


On the bench and planned for near future:

Wing Mfg. A-26 Invader 65"

Ivan Pettigrew Beaufighter 80"

Ivan Pettigrew Grumman Albatross 84"

Leo
01-07-2006, 01:35 PM
Hi Dave, I get scale performance on my 117" span Aero Commander by using the following setup:

Motors: AXI 4130/20
Props: APC-E 17-10
ESCīs Schulze 32.55K
Battery packs: E-tec 1200HP 7s4p LiPo

6200 RPM at 22 volts/37 amps
(1600 watts total of input power)
Static thrust 17 lbs.
Flight endurance 10-15 min.

Wing area is 1700 sq.in. Flying weight 28,5 lbs.

Big Oakden
01-07-2006, 08:41 PM
Large to me would be 72" + wingspan and being heavier than 10lbs.

I am looking at a 90" wingspan scratch built WWII Twin ( and I won't say which one until it is all done...THEN I will post pictures) Estimated weight with retracts and full house R/C (A,E,R,F,G) will be between 12 (estimated minimum) & 14 lbs(ABSOLUTE MAX WEIGHT)

Powered with Tanic Pacs, and PJS Motors. Calculated thrust of about 26-32 lbs of thrust at 110 amps each (rough calcs based on what weight engine will pull)
____________________________________
BradT- how much do your Skeeter and Beaufighter weigh in at?

LEO- Wish I could see her fly...How in the world did you get those Lipo's UNDER the motor mount?

BradT
01-07-2006, 11:33 PM
Leo, that is a wonderful rendition of the AeroCommander!

Dave, both the Mossie and Beau were about 10 lbs, the Mossie a little over, and the Beau a little under. Wing loading for both in the mid-20 oz. range. Both were full house, except for flaps. The gear was mech. retracts, not air. They are Ivan Pettigrew designs, which are very lightly constructed sport scale, allowing the use of lightweight, low-tech power systems. With li-po cells they would be at least 10% lighter. Unfortunately, I crashed the Mosquito beyond repair at a scale meet 2 years ago, doing a huge loop that ended slightly below ground level:mad: , and the Beaufighter last year, when a radio system failure dove it in vertically from 80'. I hope to build a new, larger version (80") of the Beau from Ivan's plans this winter.

Leo
01-09-2006, 06:37 PM
LEO- Wish I could see her fly...How in the world did you get those Lipo's UNDER the motor mount?

Hope the pictures below will clarify how the battery packs are arranged.

I have a video of the Shrike maiden flight. Unfortunately on a 100 Meg. MPEG-2 wide screen format. Iīll try to convert it and by make the file smaller: Maybe then I could upload the video at Putfile.com

Brad
Thanks. Ivanīs designs looks really good. Good luck on your projects

Dereck
01-09-2006, 09:04 PM
If you really want to see what BIG and electric looks like, David Theunissen's site at:

http://www.flyelectric.ukgateway.net/

is a place you really need to check out.

In the meantime, I have a bunch of stuff someplace in the basement from a guy who build a 1/4 scale Ryan Brougham - 127" span, around 20lb, that flew just fine on an Astro 90G, SIXTEEN round cells and a scale sized prop.

A big twin would be a cinch - though aerobatics and speed tend to cost more in all depts, so a right-side-up cruiser subject makes life a tad easier.

So does a really long van ;)

Regards

Dereck

eflight-ray
01-10-2006, 08:35 PM
Starting to think my 93" span is getting small now.
:D

Edit - Also worth looking at Ivan Pettigrew's site, some brilliant stuff.
http://www.geocities.com/ivansplans/

bhchan
01-28-2006, 07:25 AM
How about this one, arf, 88"span...all red....

http://www.hobbypeople.net/gallery/190101.asp

Lancer31
01-30-2006, 04:02 PM
I helped quite a bit in the club project, shown over to the left, (avatar,is it?), anyway, you can read about it at www.sbrcm.org (http://www.sbrcm.org) It has an 18.5 foot span upper wing.

Leo
02-08-2006, 09:24 AM
_

Ron
02-16-2006, 11:26 PM
Twins are great to fly...currently the only twin I have is a 103" catalina which is powered by a pair of magnetic mayhems on 16 cells. great model.

bhchan
02-16-2006, 11:51 PM
Ron,

Which model is that? Home made or Kit?

Brian, an EAJ

Ron
02-17-2006, 05:25 PM
Brian.....It's scratch built from Photographs and three views from Jane's...
It has retractable tip floats and retractable wheels....Slow speed steering is helped by differential throttles....( inside motor slows down in the turns)
only problem is that it's a little large to be taking out every day to fly as it won't fit in the Jimmy unless I take the wings down to 3 pieces, and they won't quite fit in the pickup truck box either...length wise unless the tail gate is down.Luckily though, the pond is pretty much at my back door so I don't have to go far with it.

rcers
02-17-2006, 06:38 PM
Here is mine - not terribly large but a nice size (48" wing)

http://www.rcgroups.com/forums/showthread.php?t=375467

It flies like a trainer, super slow landings and a true joy. It is an amazing plane. Doug Cohen my buddy did the pilot figure painting....

Mike