Hello,
I'm ready to maiden a graupner hotspot powered by EDF.
The measured weight is 9,0kg AUW.
I do not have good batteries readily available and with the ones I have I can only pull about 5 kg of thrust. With better batteries the setup can easily do 7 Kg.
Do you guys think I can safely maiden off a 100m paved runway with the weak batteries or is it a risk? I do not care for performance - just want to get the plane up in the air, trim it and land.

Thanks for your feedback!<br type="_moz" />

Hy no expert, but building a sting ray from yellow aircraft which is like the smaller version of yours and that the figures I'm aiming.

Think you are risking it.

That plane was design for a kj 66 type turbines that started giving aprox 10 kg of thrust in the old days, doubling the power in nowdays.

What setup you have? Should have a 100 to 120 mm fan and looking for .8 to1/1 power to weight ratio..

Check rcgroups has more experts and more experience guys in the forum.

Also look for the falcon edf modification which have similar size of hot spot, and see what they are using.

don't rush your maiden if not sure of your setup.


Cheers

Juan

<br type="_moz" />

I m using a 120mm, and I know it can pull over 7 kg, but simply the batteries I have right now are too weak (quite used and not that powerful to begin with).
A thrust to weight ratio of 0.8~1.0 is overkill: the habu 32 can fly comfortably at 0.5 thrust to ratio. Of course it's not ballistic, but it can take off well enough and can cruise around at 1/3 throttle.
I do agree with you on not rushing it though, I think I will maiden with new batteries then decide if I should use the weak ones as well or not bother.

Thanks.<br type="_moz" />

Hello,
In the end I decided to maiden with the batteries I had, obviously they didn't last long, but they were powerful enough and allowed me the time needed to prove the airworthiness of the airframe and to trim it. Here's the video...

[youtube]http://www.youtube.com/watch?feature=player_embedded&amp;v=jF6lLmeqS-U[/youtube]<br type="_moz" />

The hot spot airframe is a great peformer. Took of with no effort, and nice landing.

For sure I&acute;m over powered in my sting ray build.

Cheers,

Juan</p>