Help please.
 

Hi all.

I have a question and wondering if you guys could help answer. After all of the calculations i have done. Do you think an 22lbs engine is sufficient
to fly a fully fueled airplane weights in at 32 lbs? I know that in full scale aircraft, scaled down to the equivalent setting would be almost as 1 to 1 ratio. Anyway, that is
in full size aircraft so i don't know if the model airplane could be apply to the same calculations. Thanks for the help guys.

RE: Help please.
 

My super bandit is using a P70 (17.5# of thrust). The dry weight is 22#. It carries 1 gallon of kerosene so the takeoff weight is around 30#

I usually apply full throttle with the brakes and then release it. It needs 100+ yards to takeoff. It takes half a circuit to get up to speed but otherwise, it flies well. I hope the reference point helps.

Arnaud

RE: Help please.
 

Thanks for the information. Coincidentally, the reference of the full size aircraft i used to scaled down to the weight of my model was of the Rafale C, my model
is also the Rafale. The final results of my calculations for both was extremely close. What are the chances of that right. :)

RE: Help please.
 

When I first started flying turbines, I was flying a 24lb. Hotspot with a Ram 500 (12# on a good day). That was .5 to 1 thrust ratio. If you're 22lbs. dry and with a gallon of kero, you may be just slightly under 30lbs; but worst case if it is 30lbs, you'll be around .58 to 1. Are you at sea level? This will make a huge difference. If you are sea level you will be fine, it will just take a circuit or so to get "on step".

RE: Help please.
 

yf222000,

It's good that you mentionned type of jet, as this is critical. Fyi, the Rafale generates a lot of drag. For instance, my FB Rafale is powered by a P-120 (27 lbs), unfortunately, haven't weighed my jet (i should do this!!) but believe i could use more power in certain flight configurations such as steep turns, Hi alpha passes etc...

Which kit is your Rafale, and what are the dimensions??
Regards,

RE: Help please.
 

Don't forget that most of the jets at the WJM are 20kg (44lbs dry and probably about 50lbs wet) flying on P160 size turbines (35lbs).

Rgds,
Mark

RE: Help please.
 

the lighter the wing loading the less power to weight you need to fly. you could probably fly an 800 pound kite with a wren 44 but a Titan powered brick wouldn't fly all that great.

RE: Help please.
 

My Rafale was from AD Jets 1/6. It was of the older version of the kit instead of the ARF they
release now on their site now. Also, this may sounds funny, but i am not looking to do any
outrageous maneuvers that much. :) Just a Sunday fun fly and something that has stable
characteristics and enough power to to take off and landing safely. That's all. Besides, i didn't
have any special scale features that available for the kit at all, just a plain old looking bird, so
it doesn't have a lot of extra weight from the scale feature items such as pilot, lights, wing tanks,
and missiles or probe. Thanks for the info gents. :)

RE: Help please.
 

Take my word for it your going to need more thrust

RE: Help please.
 

If you think your calculations are tight, consider a slight loss of thrust when using a pipe.

RE: Help please.
 

Just FYI. The F-100 in this picture is what the BVM F-100 is built after. It weighed 35# and flew on a Ducted Fan. So I think you will have plenty of thrust.

RE: Help please.
 

Whew, love that Hustler in the background. I know that most of you gents like to have a little more power to spare,
unfortunately, this is all i can afford right now, so i have tried to cut the weight with any unnecessary items. From
all of the expertise opinions from you gents, i am confident that it is plenty there to push this old bird into the sky. Just that
i can't stand her on her tail for long or dances across the sky like that jet vid i saw here yesterday. :). Again, thank you all
for the expert ideas and opinions. I am sure i will need to ask for help from you guys soon.

RE: Help please.
 

Please, don't forget to come back and tell us how it all went after you fly your Rafale.
All the best.

Thanks,
Regards.

RE: Help please.
 

Thank you for the best wishes. Well definitely i will swing back for the update. I still have quite a bit to work on it, since
work has taken most of the time allotment and family too. You guys know how that goes. :)
I wouldn't want the wife to take seizure of the engine and left me with just the shell right.