70s Flyer

This will be my first twin,I have read all the threads from seaching all the forums.I have decided to go with OS 40 la's just for simple reliability and my old Kraft retracts for the gear.Feel free to add your 2 cents worth.Any thing I should look out for?

Thanks Rich

fancman

My Feedback: (16)

Have you read this?

http://www.rcwarbirds.com/Advisors/T...sortwinman.htm

jrf

My Feedback: (551)

I built a twin and decided to go with LA 40's for reliability. The top rpm of one of them turned out to be 500 rpm less then the other one. I spoke to Hobby Services about it and they sent me another engine. (Didn't even want the first one back!) The second engine came closer; only about 300 rpm less than the better one. This time Hobby Services told me that the LA is a great, inexpensive engine for the sport flyer, but it was never meant for twins where performance needs to be repeatable from engine to engine and flight to flight. They suggested that I switch to some other kind of engine.

Now I know that some folks say that the engines on a twin don't have to run the same, but if you are using low powered engines, as you are, and I was, a difference of 500 rpm, or even 350, is going to seriously degrade performance. I tried de-tuning the faster engine to come close to the slower one and then the airplane would barely take off. Reliable? Yes, but a good choice overall? I didn't think so. I bought a pair of Thunder Tiger 40s and the improvement was dramatic.

Jim

fancman

My Feedback: (16)

I'm with you. I wouldn't use La's on a twin either. I don't think a twin is a place to try to save a penny.

TCBLightning

My Feedback: (5)

Ditto on the LA 40's. Had a pair on my Twinstar and got sick and tired of always trying to get them to run decent. A pair of TT Pro 46s aren't that much more ($50 for both) and worth it. Plus you will love the added performance cause the Duellist was made to go fast!!

fancman

My Feedback: (16)

Sweet twin.

70s Flyer

Thanks guys,that is what I'm looking for.Ditch the 40la's.I guess I can run one in my Hammer 40 and the other in my Southern r/c Bobcat.Any other ideas?

TCBLightning

My Feedback: (5)

Order the plans from Model Airplane News and stretch the mains per that version, especially if you are flying off a grass field. Even if you have a paved runway the minimal prop clearance could cause prop strikes. My first Duellist was the Pica kit and I had way too many prop strikes.

My current Duellist is the MAN plans version Mk II and now that I am flying off grass am gratefull for the longer legs! If you stick with the gear per plans zero the incidence on the engine nacelle to the wing that will give you just a little more prop clearance.

Buy a Twinstar and throw a pair of FX 25s in it while you are building the Duellist. I went through 2 Twinstars and had finished "White Lightning" before I flew my Duellist and was glad I had some twin experience. All of my twins are or have been great flying planes when both engines are running but if you don't react correctly when you do lose an engine (I'm guilty of that), grab a bag and take it home.

There is plenty of twin advice here and on other sites by flyers with much more experience than me but that is my contribution. I'd be happy to answer any questions about building the Duellist. Drop me a note anytime.

Pictures below, first and second Twinstar, White Lightning (Tower Uproar), first Duellist (Pica kit), second Duellist (same wing, new fuse built from plans), second Duellist had a bad day....current Duellist

70s Flyer

Thanks for the great advice,I just picked up two TT Pro 46's.I need to order the updated plans next.

Build-n-flyer-RCU

My Feedback: (4)

Ditto that on using top-notch engines for your twin, that's not a good place to try to save money. I like the 46AX's on my Twin-Air. Dead reliable and easy to synch. And with Ultrathrust mufflers they spin the props good and hard. I don't know much about TT's, hopefully you will find them just as easy to manage.

I bought my Duellist used so I haven't done a full build but it looks to be pretty involved. Not necessarily a problem, but you should do all that you can to maximize reliability on an airplane that's this nice. So I would break the engines in on another airplane if you can, use good hardware, etc.

Ground clearance on the Duellist is very tight. The Jett engines on mine happily spin 9.5" diameter props at insane RPMs which helps. There's no way I could get 11" props on my Duellist. Even 10" props would be marginal. So do whatever you can to get more length on the nosestrut and build it 0-0-0 incidence as suggested.

The good news is that all the reviews are right, based on my first flights the Duellist is a really great flying airplane!

Walt