bring it on
08-12-2003, 06:31 PM
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bring it on
Im about to start my pica duelist and going to use OS 52 4-Strokes, Spring air Retracts. please tell me any mods or changes of my plans i should make are 4 stokes to big should i just go with 2 stokes? i plan on FG the plane. Please tll all
Thanks
Troy
Thanks
Troy
08-12-2003, 11:28 PM
#2
Saving Bill some time
Check out the quote below from William Robinson one of this forums moderators. Great advice on the incidence settings. Wish I would have know when I started mine. With the 4 strokes you're gonna need the pop clearance (unless you go 3-blade).
I'm in the finishing stages of glassing mine. This was my first time glassing a plane and it was sure a lot of work! Had I not went that route it would have been finished a long time ago (started building in Aug 01). There were some long breaks in between but it was not what I expected. It should turn out to look real nice once I finish painting.
I can't wait to fly it!!
Tim
Info from William Robinson,
Tim:
When you crush the fuselage while tightening the wing screws you generally remember such things. Haw.
THe TT 46 engines should give you a very good flying plane.
The Duellist tends to be nose heavy, and it's easy to end up with the plane just heavy. As you build it be sure to hollow all the blocks just as much as you can, and go light on the glue.
I was talking to Dave Platt a couple nights ago, one thing we discussed in particuler was the wing and stab incidences, and the thrust line. He agreed with my strong recommendation to build the plane with the wing and stab at zero incidence, and bring the engine thrust line back to zero-zero also. No side or up/down thrust. All his later twins, starting with the Duellist 2/40 Mk II, have been built that way. And it's easy to do as you build the plane.
If you build with fixed gear there is no problem, but if you use retracts the gear length is severely restricted, leading to a lack of propellor tip clearance.
Getting rid of the down thrust eases it somewhat, or if you like three bladed props (as I do) there is plenty of room.
As an alternate, if you want to use two bladed props, in the construction you can modify the nacelles and raise the engines about 3/4 inch. This will also allow you to shorten the nacelles a bit, since you will have room to put the back end of the tank over the wing. This also requires cutting the nacelle former away for clearance, so be careful if you do it. You could also just use a slightly smaller tank. Reason for shortening the nacelle is to lessen the nose heavy tendency, of course.
And a final mod I think is well worth while, and it's easy. Shorten the vertiical fin by 3/4 inch. Not the rudder, just the fin. Let the rudder extend below the fuselage, and put a sub-fin on the bottom to fair it in. Greatly decreases the roll cupling of the rudder. This is another change made on the D 2/40 Mk II, and well worth while. You say you're not into aerobatics? Well, it makes single engine flight a little easier too.
Just a few experience notes from the past. And present. I have two building now. Yet another Duellist 2/40 getting all the mk II mods, and an 86" span Super Duellist Mk II 2/60.
Bill.
I'm in the finishing stages of glassing mine. This was my first time glassing a plane and it was sure a lot of work! Had I not went that route it would have been finished a long time ago (started building in Aug 01). There were some long breaks in between but it was not what I expected. It should turn out to look real nice once I finish painting.
I can't wait to fly it!!
Tim
Info from William Robinson,
Tim:
When you crush the fuselage while tightening the wing screws you generally remember such things. Haw.
THe TT 46 engines should give you a very good flying plane.
The Duellist tends to be nose heavy, and it's easy to end up with the plane just heavy. As you build it be sure to hollow all the blocks just as much as you can, and go light on the glue.
I was talking to Dave Platt a couple nights ago, one thing we discussed in particuler was the wing and stab incidences, and the thrust line. He agreed with my strong recommendation to build the plane with the wing and stab at zero incidence, and bring the engine thrust line back to zero-zero also. No side or up/down thrust. All his later twins, starting with the Duellist 2/40 Mk II, have been built that way. And it's easy to do as you build the plane.
If you build with fixed gear there is no problem, but if you use retracts the gear length is severely restricted, leading to a lack of propellor tip clearance.
Getting rid of the down thrust eases it somewhat, or if you like three bladed props (as I do) there is plenty of room.
As an alternate, if you want to use two bladed props, in the construction you can modify the nacelles and raise the engines about 3/4 inch. This will also allow you to shorten the nacelles a bit, since you will have room to put the back end of the tank over the wing. This also requires cutting the nacelle former away for clearance, so be careful if you do it. You could also just use a slightly smaller tank. Reason for shortening the nacelle is to lessen the nose heavy tendency, of course.
And a final mod I think is well worth while, and it's easy. Shorten the vertiical fin by 3/4 inch. Not the rudder, just the fin. Let the rudder extend below the fuselage, and put a sub-fin on the bottom to fair it in. Greatly decreases the roll cupling of the rudder. This is another change made on the D 2/40 Mk II, and well worth while. You say you're not into aerobatics? Well, it makes single engine flight a little easier too.
Just a few experience notes from the past. And present. I have two building now. Yet another Duellist 2/40 getting all the mk II mods, and an 86" span Super Duellist Mk II 2/60.
Bill.
08-13-2003, 02:38 AM
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bring it on
Troy:
A couple notes.
I've not used the Spring-Airs, but whatever retracts you use mount the nose gear mechanism as low on F1 as you can and still have everything come up inside. The limit on nose gear length is the front wing mount, can't cut it away.
Another possibility is moving F1 forward in the fuselage, but that would have to be planned ahead, making the sides, top, and filler sheets longer to match.This could also aggravate the nose heavy tendency, so if you do it do it carefully.
When you fit the mains in the wing you can put the wheel wells right against the root rib. This gives you the longest possible main gear length. To decide how long you actually want them, by this time you should have the nose gear mounting to the point you know how long you can make it, lay it out on the side view plan, then using a yardstick you can see not only how long the mains want to be, you can also check prop clearance.
The first paragraph in the quote Tim attached was talking about the wing fillets. They are important, the fuselage is not strong enough at the rear of the wing seat without the fillets, or some other reinforcement. I also like to fill the space between the top of the wing and the threaded mounting block too, if you do this you might be OK without the fillets.
As a final note, the plane was designed for 0.40 two strokes running at a high rpm, with the smaller props they used. Your 0.52 four strokes won't be happy at high rpm, I'm afraid you'll find you have to use three blade props whether you want to or not. Or use two stroke engines. Your OS engines should run nicely with Zinger 10x6 three blade props. And Du-Bro has nice spinners to fit them. Or Tru-Turn, at $70 the pair.
Keep us informed of your progress, always happy to see another Duellist.
For your next project, I expect to see the 2/60 (twin 60 engines) released this fall, with the smaller version for 0.15 engines soon after.
Bill.
A couple notes.
I've not used the Spring-Airs, but whatever retracts you use mount the nose gear mechanism as low on F1 as you can and still have everything come up inside. The limit on nose gear length is the front wing mount, can't cut it away.
Another possibility is moving F1 forward in the fuselage, but that would have to be planned ahead, making the sides, top, and filler sheets longer to match.This could also aggravate the nose heavy tendency, so if you do it do it carefully.
When you fit the mains in the wing you can put the wheel wells right against the root rib. This gives you the longest possible main gear length. To decide how long you actually want them, by this time you should have the nose gear mounting to the point you know how long you can make it, lay it out on the side view plan, then using a yardstick you can see not only how long the mains want to be, you can also check prop clearance.
The first paragraph in the quote Tim attached was talking about the wing fillets. They are important, the fuselage is not strong enough at the rear of the wing seat without the fillets, or some other reinforcement. I also like to fill the space between the top of the wing and the threaded mounting block too, if you do this you might be OK without the fillets.
As a final note, the plane was designed for 0.40 two strokes running at a high rpm, with the smaller props they used. Your 0.52 four strokes won't be happy at high rpm, I'm afraid you'll find you have to use three blade props whether you want to or not. Or use two stroke engines. Your OS engines should run nicely with Zinger 10x6 three blade props. And Du-Bro has nice spinners to fit them. Or Tru-Turn, at $70 the pair.
Keep us informed of your progress, always happy to see another Duellist.
For your next project, I expect to see the 2/60 (twin 60 engines) released this fall, with the smaller version for 0.15 engines soon after.
Bill.
08-13-2003, 03:41 AM
#5
