SkyKnight

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Does anybody have any info or background on a project like this? The Skymaster web site has 2 pics of their twin installation which looks pretty good to me but there isn't anything else mentioned about it.

I've seen twin F18s and F15s but only twin DF Phantoms back in the day when BVM made their debut and early production run. I know there is a weight / wing loading concern. That's why I thought I would start this thread to hopefully gain some knowledge about such a project. I'd like to someday build one of these. I think of this step as my research stage.

I've only seen a kit offering such as this from Skymaster. I've sent Anton an email asking about the kit and references but he never answered. So hopefully there are those out there that can point me in the right direction. Pics of installs would be really good too!!

Thanx,
-SK standing by.......

3DAV8R

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Would also like to see more on any twin turbines out there, also looking at putting together a twin F-4

rhklenke

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Duke Chung (I hope I got his last name right!?!) did one with twin turbines (Kingtech 80's I think?) and had it at Kentucky Jets. The last I heard was that although they did get it to fly, they weren't happy with the performance - primarily because it came out so heavy, and were going back to a single. I don't remember if it was a JL or a Skymaster...

Bob

ianober

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I am selling a buddy of mine's F-4 (Skymaster) right now and he has the intakes and the fuel tanks for the twin install. All you would need is to get the formers and engine mounts form Anton for the twin install. I would think that twin P-80's would be more than enough for this plane.

Aero65

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Hi Bob

You got it correct! The twin K-80's performed well but the all up weight dry was about 45 lbs. The plane was designed to fly at about 34 ~ 38 lbs. The plane flew well and was fast, looped with authority and generally flew ok. Landing was a bit heavy but manageable. It is a Jet Legend F-4

The real issue I had was the trunions for the mains were really at the limits and were not really designed for the higher weight.

I went back to a single and cut out about 6~7 lbs, there was some reinforcement that I could not remove so the plane is heavier than stock. For our jets it just seems a better way to go is to have a single more powerful turbine rather than a twin. You will get more performance vs weight, and with our jets having pretty high wing loading already lighter really helps.

I still have the F-4, the turbine I had as the single had and issue and I had to dead stick it downwind.... not fun but it fared very well. Just have to repair it and I want to try a single pipe next. It will be an asymetrical thrust setup with a compensating gyro, and offset thrust line.

Aloha

Duke

rhklenke

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Hey Duke! Good to hear from you. Want some snow?!? [:'(] Oh, well, at least it makes for some good shop time... Are you guys going to make it to Ky Jets this year?

Bob

Aero65

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Hi Bob

Good to hear from you too. WX it pretty nice here 80 and windy, I think the Kids here might like some snow but my blood is just too thin for that lol 60 and we are wearing jackets here.

I think im pretty much retired from jet meets, it just costs too much to take our birds out there. Having to put them together and taking them apart again to send back it's just too crazy. Maybe I can convince Dave to let me fly his stuff... then it might be doable. I'm just not rich enough to have jets in 2 states lol. I know that I will miss seeing everyone there, thats the bummer part.

Aloha

Duke

yeahbaby

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you're always welcome in Texas amigo!!! all you gotta do is get on a jet and fly out here. [sm=thumbup.gif][sm=thumbup.gif]

SkyKnight

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Thanx for the input guys. I understand the wing loading will be higher and such but I still want to give it a try. These are pics I was referring to froim SkyMaster's site. ianober, I thought the SkyMaster kit could be ordered for a twin install. This one had twin P80s. I was also hoping to find some YouTubes out there as well. Duke, was yours fun to fly? Bet it sounded really kewl too!! Any video??

regards,
-SK

grbaker

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I have been disappointed in the sound of the twin turbine models I have heard. There's a big difference between the sound of twin OS .91 DFs as opposed to a single, but you just can't hear the 2 turbines in a twin turbine model. They sound just like a single to me. Or maybe it's just my hearing (or lack thereof).

rhklenke

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I'm sure Duke will chime in here, but at Ky Jets, they had some problems getting off the ground - it just didn't want to rotate. They eventually got it up, and they probably got that sorted out, but I think it was just too heavy. If you do it as a twin, I'd stay away from the P-80's (or Kingtech 80's) - too heavy. Go with two P-60's or two Merlin 90's. The Merlin 90's have all of the thrust of the P-80's but they are much smaller and lighter.

Bob

Bob Toilet

Hi
I`m waiting for my 1:7 scale F-4 twin version from Flyeaglejet. Will have two 120`s
Check out their website: www.flyeaglejet.com

Christian

Aero65

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Hey Buck

Thanks for the offer sir! I will let you know when we plan a trip there. The Wife has some family in Belleville TX so we will be heading that way one of these years.

SK

It flew ok, my friend and I both flew it. I was able to fly it both single and twin, I can say that in the air there wasn't too much difference just felt heavier in the turns needed lots of throttle in any turn. The landings were more exciting, (not in a good way lol) the sink rate you could attain on final was pretty impressive and it felt like it would be easy to get behind the elevator in flare. However that never happened to Tim or I wile flying the twin. It looked faster with the twins.

The inablity to "get it up" I hate when that happens : ) was due the nose strut compressing too much and the angle of attack on the take off roll being too nose down. We did 2 things to fix this, we lengthed the strut as much as we could and used a Robart spring to give the nose gear strut more spring. After that there were no issues rotating at all, just a couple of degrees makes the difference between a very fast jet car and an airplane with the F-4 or any delta wing aircraft for that matter.

As far as the engines go I would agree with Bob, use smaller/lighter highpower turbines. In the end I think you will find it would be much more efficent to install a larger single turbine. I don't want to be a downer, but having it as a twin was more of a pain than a benefit. Gary Baker is right as far as the sound other than the shutdown it did not sound much different. I have some video I will try and post it later this week.

Aloha

Duke

prefcon

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Hei sann

har du faatt den enda?

Jeg har tenk aa kjope samme med 2 P-160's
Bor I USA

Har hat en F-4 med 1 P-200 utrolig kuul. Se paa skymater under Egil Wigert

Egil Wigert
303 440 5053

Bob Toilet

Hei Egil

Jada, fått den, bygget den, fløyet den og solgt den. Nå har jeg FEJ F-14 Tomcat med to stk ATJ-170Ti.

Når du bygger din FEJ F-4, husk på at den blir lett baktung!!!

mvh
Christian

SkyKnight

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bump