Airbike

My Feedback: (6)

What would you guys recommend for a pair of engines to make a Super Duelist (84" span) go FAST, REALLY FAST?

I originally intended a pair of Saito 100's for this build, but I picked up the Phoenix twin from Cedar Hobbies and am using the Saitos in that.

The Super Duelist will have SpringAir Retracts and since I haven't started the build, I can incorporate pretty much anything even semi-reasonable and strengthen whatever needs strengthening.

My next up speed project: An old F-1 airframe that was never finished, and I'll install either a Rossi 80 ducted fan motor or a K&B1.00 ducted fan motor. I'm leaning towards the Rossi for weight and balance.

If the K&B1.00 ducted fan is left over, I'll just need to get one more for the SuperDuelist. Rear Exhaust pipe can be nicely cowled into the nacelles.

This will be a pretty big/draggy airframe, but I can change things as necessary.

Any thoughts? C'mon, no pair of Hebranson 280cc engines....That's a little bit overboard? I think a pair of Jett 90 or 1.00 would be a decent power package. What's the next power level up from that?

Estimated AUW to be 12 to 15 lbs??

Build-n-flyer-RCU

My Feedback: (4)

The question is how fast do you want to go?

I recently put a pair of rear-exhaust Jett 50's and pipes on a 40 size Duellist. I had just about all of the bugs worked out before I crashed it on landing a couple of weeks ago (my fault, not the airplane's). So now I have some work to do to get it flying again.

I was aiming to get it up into the low 100's in level flight. I found the Jett 50's had more than enough oomph to get it there. The tricky part was getting the aerodymic properties of the airplane adjusted to make it groove at the extreme speeds. The plane flew perfectly at normal Duellist speeds but I had some things to work out with the engines wide open. The guys on this board helped me resolve a flutter problem. Then I found that I would reach a speed where it would oscillate in pitch (porpoise). I did not get a chance to try the most recommended fix which was to move the cg forward a bit.

The Jett FIRE's and pipes really look great on my Duellist. I am sure that some larger ones would work for your Super Duellist and make it very fast, but I can't say that they would be the best choice.

If you do a search on this forum you should find the thread on my airplane.

Walt

NoOneFlysAtMyClub

My Feedback: (32)

I have a pair of Thunder Tiger 1.20RP rear exhaust pumped engines in mine. Overall exhaust length is 31". Looks very cool. Cowled in very nice. 16oz tanks. Set up as a fixed gear tail dragger with wheel pants. Want a different look. Not done yet. Needs stab and fin built. I will glass and paint when the time is right. Looks like this fall.

These engines run like a watch. Idle forever with no stumble to full throttle. Overkill? I think NOT!!

Currently finishing up a highly modified Shrike with Quickie Jett .40.

Airbike

My Feedback: (6)

Hi Walt, I saw your thread on your Duelist, bummer on the crash. I had seen pics of another Duelist with piped rear exhaust engines and it looked very clean (as far as Duelist go)

I know the Super Duelist was not designed for speed and my original intent was for a sport twin, but plans change.

If I'm gonna build this plane, I want some speed out of it! How fast? Well, I think between 150 to 200 is reasonable. I'll have to add fillets at all the fuse/nacelle/wing transitions, beef the airframe up as needed. Thin down the airfoil?? I don't even know what the current airfoil is.
Retract doors to flush out the wheel wells. Still, building from a kit is easier than building from scratch (like if I wanted a big Pond Racer instead).

I don't fly turbines, so putting two leaf blowers to make it a Turbine Super Duelist is not for me.

I'd like to get input on airframe mods, and monster engines (just short of un-do-able) we're all slightly insane anyways...

Roadtrip, do you have any pics of your install? I check on the posts over on the twin engine forum, but have not been there in a while.

NoOneFlysAtMyClub

My Feedback: (32)

Airbike

I will try to take some tonight and post them.

Tony

Build-n-flyer-RCU

My Feedback: (4)

Airbike I was suprised to find just how clean the Duellist design is with the wheels up. I would raise the retracts after a full power takeoff and it was like hitting the burners. But getting the big version clean enough for 150+ is a pretty aggressive goal. I hope you go for it because I really want to see if it can be done!

Walt

HighPlains

My Feedback: (1)

OK, ask yourself if a pair of .15's could fly the Super Duelist at 75 mph. A good sport .15 has about 1/2 hp without pipe. If so, then it would take engines with a power output of 4 hp each to reach 150 on the same airframe.

Same question, how much power to fly at 100? If a pair of .15's reachs 75 mph, then a pair of sport 40's will just get you to the century mark. Now you only need 8 times that amount of power to double the speed.

Airbike

My Feedback: (6)

At the present, I would estimate a pair of YS110 4 strokes with appropriate props to get the Super Duelist just into the 100 mph mark.

Perhaps a pair of Saito 180's w/15x10 props might make it to 110 or 120...

I think 2 strokes would be better here. Besides, I think twin 2 strokes in sync sounds better than twin 4 strokes. The twin Saito 100's on my Phoenix Twin don't really sound exciting to me.

However, I hate those ugly/bulky/heavy 2 stroke mufflers. Tuned pipes would be nice, esp with Rear Exhaust engines.

High dollar approach would be a pair of those Bob Violett big fan engines, or a pair of the YS 160 Fuel injected pattern engines (at $800 each, ouch!) ...but I tend to try and get the most bang for the buck whenever I can. Some engines ARE worth the price because the performance they deliver is unmatched. I just don't have any experience with those and would like to hear from people that have already been there/done that.

Power vs drag ======>terminal level flight speed. So I'm trying to maximize input power and then minimize the drag.
I'm not trying to build a daily flier here, so a little impracticality is ok. Only enough fuel for 3 minute flight..is ok. Look at the Q40 racers, the race is over in under 1 minute! (if you're Travis, Matias, or the handful of others that are sub-minute).

Build-n-flyer-RCU

My Feedback: (4)

I fly a pair of YS 110's on my 89" P-61 Blackwidow (23 lbs) and I agree that they could probably get the lighter and cleaner Super Duellist into the 100 MPH range. They would probably be high on my list of options if I were to buld a Super Duellist. But if you want to go really fast then of course two strokes are the ticket. You will want a ton of power and a bunch of RPM running the biggest props you can get on the airframe.

Prop clearance is an issue on the 40 size Duellist, 10" is absolute max. Not sure how it scales up on the bigger bird.

Walt

NoOneFlysAtMyClub

My Feedback: (32)

I dug the Super D out of the corner and took a few pic's for the interested.

I built the wing one piece. Going with shorter ailerons. Full length ones are not needed and prone to flutter.

I built the stab and fin to plans. I intend to replace both. With the 1.20's the fin seems small and the stab looks and feels like it will fail with any elevator input.

Back to the engines. I have been running 15X10 wood props for both bench time and flight time. My flight time is with a giant Ultra Lite stick. Big fat wing, 80 some inches, quad flaps. Slow airframe. Even slow in a power dive!!! Not a good way to find out a engines potential. Might have to build something a little faster for prop testing prior to flying the Super D. So far I have been running the header uncut with a Mac's muffled pipe. With the 15X10 I am taching 9600rpm on the bench. I think a 14X13 or 14X14 APC might be the prop to go with for the Super D. I am reluctant to do much cutting on the headers until I get a better airframe to test with.

Thats it. Here are a few pic's.

Tony

Airbike

My Feedback: (6)

Thanks for the pics Roadtrip, wow, those tuned pipes are pretty long, I think the pipe for my K&B 1.00 are long too, I haven't really examined the setup (bought used from another go fast guy).

I think this project will be another one of those that takes forever to plan out before the construction begins.

NoOneFlysAtMyClub

My Feedback: (32)

Airbike,

I built mine up to this point and said now what?

A friend talked me into pylon racing and I have not touched it since. Been over a year now. Now I just work on go fast stuff. I need to finish it though.

I am going to have to fabricate some kind of a mounting system for that 31inch exhaust.

Tony