JimBrown

My Feedback: (2)

Bill,

I've been lurking. Keeping an eye on who's building the 2/60 and what they're doing with it. Someday I hope to have enough time to take the wood out of the box I have. :-)

By the way, did you notice what I'm using to attach the retract unit to the plate? Figured I'd make that the weakest link. Better than ripping out the plate or breaking the retract. Heh. Here's a better view of that little idea...

...jim

William Robison

My Feedback: (3)

Jim:

Nylon 4-40 screws? Great idea, I like it.

Bill.

JimBrown

My Feedback: (2)

That would be them!

I'll let you know how well they work next year (which is when I should have that project completed...)

I've been using 1/4-20 nylon bolts on my giant scale tail draggers with great success. If I happen to make a lousy landing (doesn't happen so much now... heh) instead of ripping the landing gear mount out of the airframe, it just breaks the bolts. If no other damage, the plane is airworthy again in a couple of minutes. Purchased a bag of 1/4-20 socket head bolts from Microfasteners a couple of years ago. Still have lots of 'em.

...jim

Blade47

Well I have almost cycled through all the planes I have flying so I may get another chance to fly the twin this weekend ...I was kinda hoping to have a Twin-Sync system in place but what the heck the throttle hardware is close now ( just have to do a better job of tweaking the top end ).

Bill: how are your test with the TS system coming out?

Is there anyone else close to test flying there 2/60 out there? or 2/40

Seem to me that there is always one plane in your fleet that is your favorite to fly.... so ... until we have more info to post on the 2/60 how about posting a pic of yours.

mine is a Strikemaster with a converted "T" tail ST.90 in the nose. I have even had it with a "V" tail and side speed breaks doors.

timfarrar

Pete :

I hope you ment anyone ?
I have so many favorites, but Ill try and narrow it to my Corsair and Sopwith Pup. Also I would like to show my nephews Ultimate bipe, It is beutifull !
And one more, Its not a favorite, but it is the funnest. (Katana) Lizard is my nick name for my wife.

SEEYA, TIM

Blade47

Yes you bet Tim anyone can drop by and post.... Very nice collection you have as well Tim

redtail

My Feedback: (15)

Hey Guys, need some advice. Would like to use a pair of 4-strokes in my 2/60. Any advice or wisdom on what size and/or brand to use? I really want to hear the sound of two 4-strokes. HELP? Chic

fastpat

If you can work out the weight and balance issue, I'd say take a look at a pair of new YS-110's. Lot's of power, but somewhat weighty.

jrf

My Feedback: (551)

For speed and vertical go with Saito 100's. For sound and reliability at a very reasonable cost, use Magnum 91's. Basically, every 4 stroke manufacturer (except YS) has a 91, so pick the brand you like best.


Jim

William Robison

My Feedback: (3)

Chic:

I am currently assembling a plane similar to the Super Duellist 2/60 Mk II, I'm using Saito FA-82 engines in it. They should also fly the SD 2/60 nicely, but I don’t think they would give the performance the SD is capable of giving.

My choice for the SD would be either the FA-100 or the FA-125. Problem is weight. The 82 is 16 ounces, similar to a two stroke in the size range the Duellist 2/60 wants, but the 90-91 two stroke will be a lot more powerful. Wont sound as good, granted. When we go to the FA-100 engine we’re up to 20 ounces each, or the FA-125 at 22 ounces. If I were going four stroke in the Super D I’d most likely go with the 125 Saito engine and in some way compensate for the weight.

Problem is the Duellist planes tend to build nose heavy, the added engine weight just makes it that much worse. If you’re really aggressive hollowing the blocks, then putting the battery behind the wing might work. There is no provision for rear mounting of the tail servos, might find it’s necessary with the four stroke engines.

So. The FA-82 engines will fly the plane, but not a lot more. The FA-125 engines will give the performance the plane is designed for, but there might be balance problems.

Bill.

PS: Because of the weight Saito is the only four stroke I'd consider. wr.

jrf

My Feedback: (551)

Bill:

I don't have an SD 2/60 so maybe I'm missing something, but isn't it designed for 60 2-strokes? A 60 2-stroke with muffler will weigh 24 ounces or so (The OS 61 FX is 23.6). The Saito 100 with muffler weighs 20.9 ounces. The Magnum 91 4-stroke weighs 22.4 ounces. Sounds to me like the 4-strokes would be easier to balance.

Jim

William Robison

My Feedback: (3)

Jim:

People who want to use the heavy 60-61 engines have the balance problem too.

Dave Platt, in designing the original Duellist 2/40 used the K&B ringed 40 engines, about 12 ounces per engine. When Ernest Fleming and I did the Super Duellist 2/60 Mk II we wentwith the K&B engines again, the ringed 61 6550 is almost as light as the ringed 40 engine.

Perhaps we were remiss is not considering heavier engines, but with the long nacelles even a 20 ounce engine can be a bear to balance without weight in the tail.

Bill.

Flyboy Dave

My Feedback: (21)

Bill....wouldn't just be easy enough to back-set the engines a inch ???

FBD.

William Robison

My Feedback: (3)

Dave:

The Duellist design uses all the skin, both the fuselage and the wing, as the main load bearing part. The inner structure by itself is fairly weak. That’s why the nacelles are glued to the outer surface of the wing with no cuts, either to the leading edge or the wing skin.

It would be easy to move the firewalls back, but since the fuel tank takes up the space between the firewall and the wing leading edge a smaller tank would then be necessary.

If you can get enough fuel for the length of flight you like, then no problem.

But DO NOT cut into the wing of a Duellist – you will weaken it.

Bill.

Edwin

My Feedback: (2)

William,
What size tank do you think will fit in the nacel. I pretty much decided to use ST.90's. Need to find a better muffler for them though. Tail mounted servos shouldnt be too much a problem.
Edwin

Blade47

Gentlemen! One more test flight was made but ended in structural failure of the Stab [X(] I had changed up the props on the engines to 12x6 Dan and I tweaked out the engines and all sounded sweet ... Take off into wind of about 7 mph right down the runway lift off with about 3/4 throttles.

Got one full circuit motors sounded fine and was just coming out of the down wind leg come up to full power and with the gear still down ....Just finished the roll out into wind engines at full power and Dan and I could see the right stab starting to make like a duck wing flapping by itself there was NO advanced sound of flutter and by the time I got the power off it was to late and seen the stab half flutter away .... almost gave up on the flight but stayed with it and was able to fly it into the down wind leg ...started to bring it down but when I got it into wind I had the power off and the nose came up into a high stall ... killed both engines and it dropped on its own to the low bush.

So now .... to sit back and try and figure this out ...never had this happen to me before .... just a clean break at the fuse side where the stab goes in ...Hmmmmmmm ...any ideas????

Crap having a problem posting the pics again .....Bill??? can I send them to you and you post ... Or Don ??

William Robison

My Feedback: (3)

Pete:

I’m going to guess the fickle finger got you. Did you cover the stab, and then cut the covering away for the glue joint? That’s where thje fickle finger comes in – creasing the wood while trimming the covering will leave a weak spot. Usually nothing happens, but often enough the wood will fail. To make it worth a caution. Most ARFs have a caution about it in the instructions. Had it failed anywhere on the span except against the fuselage I’d be inclined to think we didn’t make it strong enough. At the time I thought about an arrow shaft, either FG or CF as a stab spar, we didn’t do it. Might be something for everyone else to think about, and you might add one in doing the repair.

Hope it’s not too bad.

Yes, send me the pictures, I’ll post them for you.

Bill.

Blade47

Hmmm have gone over the part about the covering and no it seems to me that I didn't cut into the balsa ... what I do for the covering is put a strip about 3/4" wide in the angles and bring the covering up to it ...so no ... it was not a cut to the wood ..... as you will see in the pics it didn't even fail at the built up part of the stab ...it broke right on the solid part of the balsa center block and NOT even at the edge where the cross braces are ... Hmmmmm

William Robison

My Feedback: (3)

Edwin:

Sorry I didn’t get back on this sooner, I had intended to do it last night and then forgot.

The tank SD 2/60 tank compartment is 5 5/8” long, 2½” deep, and 3 1/8” wide. The Du-Bro number 412 tank, 12 ounces, fits nicely.

Bill.

Blade47

I sent them to you Bill

William Robison

My Feedback: (3)

[Also, to all who might be thinking about mounting servos in the rear.

Remember the fuselage and wing skins are the main strength of the Duellist design, any cuts anywhere can weaken the airplane. If you do mount the servos in the rear be very careful to make sufficient reinforcements.

Bill.

William Robison

My Feedback: (3)

Pete:

Here are your pictures, I combined the separate shots of the end of the stab.

After looking at them I rather think we should have included the CF spar. At the same time, no one else has had a problem. Granted, not that many flying, but no problem reported from any others.

Another possibility, looking at the picture of the separated nacelle, I see there wasn’t any glue adhesion showing on the lower wing surface. Do you think it’s possible you just had some bad glue joints in the rear also?

Bill.

William Robison

My Feedback: (3)

Pete:

Reinforcing the thought of poor glue adhesion – look at the LE of the stab – no tearing, no wood transfer, almost as though it hadn’t been glued at all. Like the lower sides of the nacelle.

Bill.

Blade47

Hmmmm .... I will have to take another picture of the bottom of the wing ..you will then see that the nacelle had good contact with the wing skin and the glue ...this nacelle took the brunt of the crash and just tore away from the skin....but all things are possible.


as for the Stab .... it did not break at any of the glue joints .... The Balsa center that the rest of the stab is built up on failed ...it is very hard to see in the pic .. I will try and get a better one when I take the covering off the damage area.

Thanks for posting the pics Bill

Cheers

timfarrar

Pete :

Sorry your plane got damaged, but it doesnt look to bad from the pictures. I do realize that even a scratch on a new plane feels terrible. Youll have it back together in no time.
Im no expert, but it looks to me you just had a piece of soft balsa in that particular spot. It was just to lite to handle the stress back there.
Maybe when glueing it back together, you could use some of those flat carbon fiber strips. If you do that, you may be able to just glue that one back together and cut a trench down the length of the stabilizer for the carbon fiber to lay in. After that it would be plenty strong.

Good luck, SEEYA, TIM