Duellist as a twin trainer for a ziroli B-25
09-20-2005, 11:46 AM
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Duellist as a twin trainer for a ziroli B-25
hi y'all,
I'm planning to start building my pica kit for the duellist in the near future. I'm in the process of building the 101" version of the ziroli B-25, but I want to have some hands on twin experience first, so that's the reason for the duellist. I chose it for looks, and for the engines I had lying around: a couple of OS FS 48 four strokes....nearly all my planes are powered by four strokes... easier to keep quiet (noise regulations at our club are very strict!), very reliable,they last longer than most two strokes, and in my opinion, are more fun to fly!
No, as for the duellist: some questions come to mind: as it is the pica kit, its a MK1. The odd wing and thrust setup bother me somewhat. I read in some other posts that the setup on the MKII is 0-0-0
(wing-stab-thrust). Can I simply change the angles on the MKI, Or did the MKII have a different wing altoghether???
Any insights on performance with these engines?? (I do have two OS SF 46 engines as well, a regular and a brand new contra rotation, but if I use these, I won't be able to fly it at our club, so they stay on the shelf!)
how about bringing the engines in closer to the fuse, for added single engine stability?
About the B-25: Has robart retracts, Glennis scale wheels + brakes, two Saito 150's for power, and a whole lot of servo's!!! I'm building it with the closed 8-gun nose (the "strafer" version)
is now 50% complete..... time to start building the duellist, and another plane to run in the saito's......
Happy flying!
Wim
I'm planning to start building my pica kit for the duellist in the near future. I'm in the process of building the 101" version of the ziroli B-25, but I want to have some hands on twin experience first, so that's the reason for the duellist. I chose it for looks, and for the engines I had lying around: a couple of OS FS 48 four strokes....nearly all my planes are powered by four strokes... easier to keep quiet (noise regulations at our club are very strict!), very reliable,they last longer than most two strokes, and in my opinion, are more fun to fly!
No, as for the duellist: some questions come to mind: as it is the pica kit, its a MK1. The odd wing and thrust setup bother me somewhat. I read in some other posts that the setup on the MKII is 0-0-0
(wing-stab-thrust). Can I simply change the angles on the MKI, Or did the MKII have a different wing altoghether???
Any insights on performance with these engines?? (I do have two OS SF 46 engines as well, a regular and a brand new contra rotation, but if I use these, I won't be able to fly it at our club, so they stay on the shelf!)
how about bringing the engines in closer to the fuse, for added single engine stability?
About the B-25: Has robart retracts, Glennis scale wheels + brakes, two Saito 150's for power, and a whole lot of servo's!!! I'm building it with the closed 8-gun nose (the "strafer" version)
is now 50% complete..... time to start building the duellist, and another plane to run in the saito's......
Happy flying!
Wim
09-20-2005, 01:33 PM
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RE: Duellist as a twin trainer for a ziroli B-25
[b]Wm:
I have to assume you are saying the SF 46 engines are too loud for your field. If this is why you can’t use them OK, but they are about the minimum for “Spirited†performance with the Duellist 2/40, either Mk I or Mk II. I’m sure it will fly with your 48 4s engines, but it will be neither exciting nor a challenge, except maybe keeping it in the air with them. The Duellist tends to build heavy, there are a lot of thick planks and blocks that often don’t get hollowed as much as they should.
You can alter the fuselage during construction to bring the wing and stab down to zero incidence, and raise the engines to zero also. Eawy to do with the stab, the wing takes a little more care to do.
An alternate is to bring the engines up to a +2 degree thrust line, then the relationship of the wing, stab, and engines is still 0-0-0.
Talking with Dave Platt when we were doing the al;teration to make the Super Duellist 2/60 Mk II, he said the one big mistake he made with the original was not making it 0-0-0 also. His thought at the time was the angles would make the plane a better trainer, and while it did that no body built it with the intention of using it as a trainer. The Mk II is 0-0-0 from the start, it’s a lot better plane for aerobatics. So it’s up to you. Change the fuselage I the build, raise the engines, or leave it as drawn. Another good thing in raising the engines and leaving the wing and stab as they are – much better propeller clearance.
One thing you do not have any need to do is moving the engines closer to the fuselage. It just would not look right, with so much span outboard of the engines, and engine out is a non-event anyway. It has plenty of rudder, and Vmc is not much higher than stall speed anyway.
Yes, the wing on the Mk II has a little more span, and two more ribs (one in each panel) than the Mk I. Most obvious difference is the empennage. The Mk II has the vertical fin lower, and a subfin added. The rudder has a balance area over the vertical fin where the Mk I has a fixed vertical fin area over the rudder. Other than that, the two versions are very hard to tell apart. The changes to the tail are well worth while, removes a fair bit of the roll coupling the Mk I had.
Enough for now.
Bill.
I have to assume you are saying the SF 46 engines are too loud for your field. If this is why you can’t use them OK, but they are about the minimum for “Spirited†performance with the Duellist 2/40, either Mk I or Mk II. I’m sure it will fly with your 48 4s engines, but it will be neither exciting nor a challenge, except maybe keeping it in the air with them. The Duellist tends to build heavy, there are a lot of thick planks and blocks that often don’t get hollowed as much as they should.
You can alter the fuselage during construction to bring the wing and stab down to zero incidence, and raise the engines to zero also. Eawy to do with the stab, the wing takes a little more care to do.
An alternate is to bring the engines up to a +2 degree thrust line, then the relationship of the wing, stab, and engines is still 0-0-0.
Talking with Dave Platt when we were doing the al;teration to make the Super Duellist 2/60 Mk II, he said the one big mistake he made with the original was not making it 0-0-0 also. His thought at the time was the angles would make the plane a better trainer, and while it did that no body built it with the intention of using it as a trainer. The Mk II is 0-0-0 from the start, it’s a lot better plane for aerobatics. So it’s up to you. Change the fuselage I the build, raise the engines, or leave it as drawn. Another good thing in raising the engines and leaving the wing and stab as they are – much better propeller clearance.
One thing you do not have any need to do is moving the engines closer to the fuselage. It just would not look right, with so much span outboard of the engines, and engine out is a non-event anyway. It has plenty of rudder, and Vmc is not much higher than stall speed anyway.
Yes, the wing on the Mk II has a little more span, and two more ribs (one in each panel) than the Mk I. Most obvious difference is the empennage. The Mk II has the vertical fin lower, and a subfin added. The rudder has a balance area over the vertical fin where the Mk I has a fixed vertical fin area over the rudder. Other than that, the two versions are very hard to tell apart. The changes to the tail are well worth while, removes a fair bit of the roll coupling the Mk I had.
Enough for now.
Bill.
09-20-2005, 03:24 PM
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RE: Duellist as a twin trainer for a ziroli B-25
thanks for the reply.........
so your message is: build light! and yet I plan to install retracts......... (have a set of rhoms lying around.......)
What would the SF 46's give like performance? I guess contra rotating (one is a reverse rotation) would be great on a twin, but prop selection would be rather limited, right???
I guess I could silence them to the point where it would be possible to fly at our field, but that would mean low rpm's, big props, large mufflers......and less reliability......can't recall having a four stroke quit on me, other than the two times I busted my spring valves on a FS 70 and FS 90........
Happy flying!
wim
so your message is: build light! and yet I plan to install retracts......... (have a set of rhoms lying around.......)
What would the SF 46's give like performance? I guess contra rotating (one is a reverse rotation) would be great on a twin, but prop selection would be rather limited, right???
I guess I could silence them to the point where it would be possible to fly at our field, but that would mean low rpm's, big props, large mufflers......and less reliability......can't recall having a four stroke quit on me, other than the two times I busted my spring valves on a FS 70 and FS 90........
Happy flying!
wim
09-20-2005, 03:44 PM
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RE: Duellist as a twin trainer for a ziroli B-25
[b]Wm:
Most Duellists come out at 10-11 pounds, some over 12. With much care it can be done at 9 lbs. AUW, Think I heard of one at 8 pounds. That would take some "Doing" to keep it that light, and some really light engines too.
Give it a try with the 48s, you an always pop them off later.
In this country reverse pitch props are easily available from Zinger, tney make almost anything you want in both left ande right rotation. Also wooden three and four bladed props. Again, as both L/H and R/H.
[link=http://www.zingerpropeller.com/index.htm]Zinger web site[/link]
I don't know how easily you can order from across the pond, worth a try.
Bill.
Most Duellists come out at 10-11 pounds, some over 12. With much care it can be done at 9 lbs. AUW, Think I heard of one at 8 pounds. That would take some "Doing" to keep it that light, and some really light engines too.
Give it a try with the 48s, you an always pop them off later.
In this country reverse pitch props are easily available from Zinger, tney make almost anything you want in both left ande right rotation. Also wooden three and four bladed props. Again, as both L/H and R/H.
[link=http://www.zingerpropeller.com/index.htm]Zinger web site[/link]
I don't know how easily you can order from across the pond, worth a try.
Bill.
