Lift off speed Supa Pup

[Russty]

Hi, Can anyone tell me the approx. lift off speed of a supa pup, say with 80kg pilot, 20kg fuel, 4cyl 4 stroke KFM motor, on a 10 degree still winters morning, say altitude 1000ft ASL. Assuming tail lifted & elevators level. I intend doing some ground runs soon & this is good info to have. I believe that stall speed is around 38 knots?? Is it a hard stall in this plane?

 

 

[Russty]

I inadvertently put my above questions on the Microlight area.

 

'Ducky' answered there so I will post it here also:--

 

"G'day everyone,

 

Since my last post I have now got 13 engine hours up and 8 hours flying time. I have explored the stall and flap use and all is good. At almost all up weight the clean stall came in at 44 kts, 10 degres flap 43 kts, 20 degrees flap 42 kts. The stall is very gentle and tends to want to "unstall itself" as soon as it occurs.

 

The ailerons are very very responsive, so until you get used to it you are all over the place, I'm used to it now. My oil temp is still sitting at the top side of the green band, so a bit more tweaking of the cowl openings req'd and the cht is in the green band at 325 degrees F.

 

So far I have done about a dozen landings and at the moment I need to really fly it on and pin it with forward stick as soon it touches. The landing gear shock absorbsion works well.

 

 

[Steve Neal]

Gday Rusty, I’ve got 220 hrs now on my Pup MK4 with Jab 85 hp- cruise 90 knt @ 2650- stall 42 clean- 40 1/2 flap- 38 full flap. Could never get on top of my oil cooling until I modified the air intake over the oil cooler now it’s fine, how do you attach a pic to this chat? when I can get it to work I’ll send one through. Steve.

 

 

[Steve Neal]

Hi, Can anyone tell me the approx. lift off speed of a supa pup, say with 80kg pilot, 20kg fuel, 4cyl 4 stroke KFM motor, on a 10 degree still winters morning, say altitude 1000ft ASL. Assuming tail lifted & elevators level. I intend doing some ground runs soon & this is good info to have. I believe that stall speed is around 38 knots?? Is it a hard stall in this plane?

Sorry Rusty forgot to mention lift off is @ 50

 

 

[skellywelly]

@Russty Good to see someone else using a KFM engine.

I have a kitfox mk2 with a KFM112M.

How do you get on with your engine ?

Do you know where I can find any spares ?

Cheers.

Skelly.

[facthunter]

Lift off speed will vary a lot on your circumstances. What you need to cover is what stall margin you carry for your weight and flap settings and wind gusts AND runway surface. like grass length and water, and how rough the surface is. Some uneven surfaces will shoot you into the air before you are ready in which case you might (have to) fly in ground effect till you get the right speed rather than settle back especially if a crosswind is involved. A tailwheel plane will fly off at a set angle a bit more taildown than cruise but often a clean unstick is desired (like in a x wind) so you will hold it on the ground a bit longer and make a more positive rotation. at the higher speed. rather than let it fly off when it feels like it and have another ground contact after the initial ift off. 1.3 Vs should give a margin enough for most circumstances. If you plane is quite power restricted all this should be done sensitively as if it gets on the slow side it's not going to get out of that very quickly.. Height and temperature drop performance a lot. Nev