hi,

I would need some experienced people advice...

I'm on the way to make a f22 (1.4m wing span)...I am not sure if I want to direclty put a turbine inside as If it crash it would be costly...
I am thinking of putting ducted fan system with os 91 and ramtec 5" fan for some time...

There is differents points on which I am not really sure of what to do:
- putting directly the turbine...(I think this is the worst idea...lol)
- putting one engine...(will thrust be enough to fly???)
- putting two engines...(would be better but would require some adaptation when I will finally put the turbine..(exaust pipe to be bifurcated...inlet pipes...etc...).

the carbone fiber plane estimated weight is around 9kg loaded...I hope it will be less but for safety I take some margin...

Hello.
I would not go through the hassle of flying it with d/f first. It will be a huge effort to convert the d/f setup back to turbine...set it up turbine from the beginning, then everything will be neat and tidy and you will have a lot less work and "unused mounts" in the end.
Even though a crash is costy, it will always be, even if you opt for d/f.
Another important thing to look at: in a crash, the turbine is hardly ever fully destroyed. Mine came out fully undamaged with the loss of the plane (was able to shut down before impact), and with all the crashes i have witnessed, all but 2 turbines came out with no or minor damage.
I think you will be a lot happier if you go turbine from the beginning. Did the same thinking on my Avonds F-15 some time ago, now it's going out as turbine....
Just my opinion

I agree on the fact that a crash is always expensive...For the turbine itself, I am not too much afraid as is think its body might be damaged but not everything so repair/setup cost would be...lets say...ok...
but if engine is not cut on time...then should run fast!!!! then you just have your eyes left to cry...

I will wait for some other people advice, but yes after thinking little more, I suppose you are right! (its so bad to modify a plane when it is done lol)

Testing a Jet with a DF is pretty much useless, you didn't have the power and the speed that will put the real test in your airframe. Go without hesitation to the turbine
option, check twice all systems, CG and throws and go for it!


Rgds, Enrique

Go Turbine

More reliable and IF things do not go well, you can still have the turbine repaired


Regards.............. Johnny Hernandez

I agree. I have flown both and would take a turbine over a DF any day. DF's are such a pain. Like what has already been said Turbines can be repaired a lot of the time for about the same cost of a new DF .91 and fan.

Dave

thanks for your comments...I will follow them :-)))