wildnloose

Search youtube videos for Paul Appelbaum to see all of his foamie X45 conversions. I am going to convert my FW Avanti as well.

jvaliensi

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Paul's videos are really good. They are worth watching just to learn fabrication tips.
He is against single walled pipes in foamies. However, I have seen many videos of single walled pipes in Avanti's.
So, either way must be okay.

wildnloose

I agree about the single wall pipes, as long as you cover the foam area as well. But I am a dual wall pipe fan myself and that's what I plan to use. I am in no hurry as it will take me a long time to save my pennies. I have a friend who has already started on converting a Eflite 90mm Viper (with smoke). Its a little bigger than my Avanti and just looks like its made to convert to turbine. He has been flying turbines for a while now and has his own way of doing things. He is also a dual wall pipe fan.

Viper1GJ

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The Avanti I saw fly last weekend use the stock HAB kit with a single wall pipe. It worked fine but I prefer double wall pipes. Paul I think still produces them for sale.

Tay3

FYI

My FW Avanti uses HAB kit with x45 turbine.
Terribly great mixture, great fun.
There is about 15 flights through it and the inside of the jet’s , foam is as smooth and Bloch free as the day I got it. Yes I used the aluminium tape.

Two walls might be better, but it is going to be heavier and at the far end of the exhaust, watch the C of G.

wildnloose

Actually the dual wall setup weighs less than the single wall/tape setup. That tape is heavy.

jvaliensi

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The aluminum tape I bought weighs 4g for a strip 3" wide and 12" long. There is about 5 of them in my Avanti, so that is 20g.
That makes the HAB pipe install lighter than a dual wall pipe.

DUCMOZ

I converted a Stinger 90 to Turbine a few years ago and used a single wall pipe with 2 coat of BVM heat shield. The plane has had over 100 flights without any issue or discoloration. The good thing about BVM heat Shield is that it is white and to me looks a lot better over the foam than aluminum tape and does not lift or comes off.

Behzad

powerjets

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The big HSD (foam) T33 is an excellent flyer on a K45, it needs some energy management, but flies great.
it actually still has a higher power to weight ratio than the full size had.

Viper1GJ

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This is the FW Mig-21 my friend Keith converted to turbine back in 2020. I bought it from him and flew it for a while and then sold it. I was asked recently to share my photos of the conversion online. Here they are for anyone interested. The description is here: Foamie jet for X45/K45 ?

Viper1GJ

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FW MIg-21 turbine conversion photos continued...

oachidori

I just finished my conversion of the F22 with x45 turbine. Weight is around 3700 without fuel. The plane flies awesome even the time is around 5 min of flight due to the bifurcated pipe. I cannot put pictures, i have not the right yet.

Viper1GJ

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F-22 is one of my favorites. Flies great and looks way cool doing it. Make a bunch of short posts on any thread till you get your 10 in and then show us your photos.
Gary

oachidori

Some pictures i already put on fb, on the small turbine jets. I bought the conversion kit from bigboys rc with bifurcated pipe and from my side looks awesome. Probably i may wrong but did you use a heatshield instead of aluminum foil for a Eurofighter conversion?

Viper1GJ

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Yes I used the painted on heat shield and not the aluminum tape. The tape is very heavy and sometimes does not stick well on curved parts. Most of the time in my experience it is not needed if there is plenty of cooling air and a double wall pipe.

oachidori

Understood, you re right. I didn t knew that there some paint i could used instead of the foil that came with the conversion kit. I really was quite difficult to put the foil in the curved areas but at the end i suppose was just ok. We will see. On the other hand i cannot use a double wall pipe ate least in my opinion due to the configuration of the plane. As i wrote even probably i lose some power with the bifurcated pipe but looks like an F22. I saw many other types of conversions where some people put the turbine at the back of the plane but i didn t like these options.

Aussie1

I made my own custom single pipe, and by making it oval, managed to fit it inside the existing duct. Certainly doesn't lose any thrust and enabled me to put centre burner lights either side of the pipe.

oachidori

Yes,
i know your build, i already saw it. In this setup can you tell me how big is your main tank and your during flight? If i well understood i lose some power and also more consumtiont of the fuel with my bifurcated pipe but i am interested to know what is the difference.
Thanks,

oachidori

[QUOTE=Aussie1;12774041]I made my own custom single pipe, and by making it oval, managed to fit it inside the existing duct. Certainly doesn't lose any thrust and enabled me to put centre burner lights either side of the pipe.
My bifurcated pipe from bigboyrc weight 100 g, so only 25 in plus, but looks different even i lose some power unfortunately because of that.

Aussie1

[QUOTE=oachidori;12774080]I have flown my F22 in formation with another one using the X45 and the bi-duct, and we did notice a large difference in level speed and vertical climb. We estimated that you will lose about 20% thrust with a bi-duct. My tank is a one litre water bottle and a felt clunk, no header, which will give close to 10 minutes till empty, and I have never had a flame-out. My pipe is reasonably light, and with a 3s 2200 RX LiPo in the nose cone, balances without nose weight. Regarding my pipe, I increased the diameter of the last section by 10% due to the fact that a circle when flattened to a oval, loses some area. This is from Quora, Conclusion, if the circle and ellipse have the same area then the ellipse has a greater circumference than the circle. This calculator gives you a idea of how much bigger the perimeter of the ellipse has to be over the circle circumference, so as not to restrict the pipe air flow. https://www.spikevm.com/calculators/...le-to-oval.php

One litre water bottle and felt clunk.

oachidori

Understood. Before to buy the conversion kit because i don t have the knowledge or how to made an exhaust pipe i searched on the net what solution have chosen others. My friend with the same plane told me to buy this kit because it is well calculated. Probably he omitted to tell me that i will lose some power and also a bigger consumption of fuel. But at the end it is the first jet, after a while when i will manage the plane better will pass to the next level, F22 composite with two X45. There is a producer Christen diffusion that make a plane with the good dimensions for this. 2 m length, around 8-9 kg in function of the plane setup.

Aussie1

This jet is quite overpowered with the X45, so the performance with a bi-pipe will still be way better than when you fly it with the stock EDF.

oachidori

That i took the decision to pass from EDF to turbine. As i saw exactly how you wrote it is better than the EDF power.

oachidori

I flew over the weekend my F22 and a friend of mine with the same X45 but on a Rafale and of course straight pipe, the Rafale was stronger that mine, it seems when it flies at full speed and when it takes off. Because of that i want to build another F22 but this time with straight pipe not bifurcated. Having 45 mm diameter of the tube from the site you gave it to me, i saw that having short axis 25 mm, maxim at F22 is 35 mm, so i supposed to let 5 mm for cooling, will have the long axis around 81 mm. I will ask a company if they could make me this pipe. Do you think is correct? The length as i calculated will be 240 mm, remaining 10 mm out of the plane.

Aussie1

I made my own custom pipe for the F22, detailed earlier in this thread. The pipe is in two parts, forming a oval on the exit, this allows it to fit within the foam thrust cavity. I also found that I had a slight increase in thrust with my pipe from the X45, I'm guessing that this is due to the convergent to divergent design. This style of pipe was pioneered by Mike Wren many years ago, when he proved that the right pipe design could increase a turbine thrust level slightly, and in my case I measured just under 11lbs of thrust.