ModellbauUK

I wonder if any one can help with a few questions.

Am just fitting the Kingtech K80F into a Jet Legend F15

Is it necessary to use the lower half of the bypass or could I just mount the turbine directly to the rails?

I don't propose to use the upper half of the bypass either. Will not using the bypass make that much difference?

I presume the front cone would need to be fitted to the tailpipe if not using the bypass housings. I will line the area around the turbine with foil tape as a heat shield

Also, is the tail pipe horizontal centre line level with the top surface of the turbine mounting rail?

Thanks for your help

Ian

whitcombe

Ian, I have a jetcat 120 in my old JL F-15 so turbines should be the same diameter. I only have the bottom half of the bypass fitted with no issues what so ever. You could leave it out altogether and it wont make that much of a difference if any at all.

All the best

Tim

bluescoobydoo

had one with a wren 160 no bypass needed leave off the doors and rudder servos they are a waste of time aswell

ModellbauUK

Thanks guys

Do you think a k80 will be under powered at max thrust (suppose it depends on weight ready to fly)?

Did you use all the available power from the P120 and Wren 160

Bought the model nearly built, rudders and gear doors already fitted.

Ian

bluescoobydoo

the 160 was way to much power, it was less than half power in the cruise and made it a bit on the heavy side and only got about 7 mins from the tanks if i was building another one i would glue the rudders and remove the doors as they just add weight and require all the bits to get them to work which also adds weight and the flying does not suffer without them, i would also fly tailerons only and glue the ailerons up as well, the k80 will fly it no problem the first jl f15 flew on a 14lb turbine

ModellbauUK

Thanks very reassuring. May trim bits once I've flown the bird

jeff sewell

My Feedback: (1)

Hi Ian
I personally believe that a 18 pounds thrust would be the minimum that you would fly the F15 with preferably more!
Leave the bypass and use a bellmouth instead, no doors and fly tailerons. My preferred turbine size would be 120 to give a bit of excess power and 'full house' controls but still wouldn't bother with the bypass!

Jeff

jroth

My Feedback: (60)

Hi,

I have one of the early Jet Legend F-15s from Global Jet Club, I tried to fly it with an AMT Mercury and it barely flew, it would not loop and it was sagging in the turns. This engine had about 17 pounds of thrust. I installed a Jetcat P-120 and now the plane flies properly. I need to work on moving the cg back, the landings are way too fast.

Good Luck,

John

Jetpilot24

My Feedback: (21)

I have a Skymaster F-15 with the K-140 in it. I cruise at about Half throttle and when I hit the throttle for what I call Ridiculous Vertical, It s great. I too use Half bypass to create a little more drag when landing. Full bypass gives you a very clean setup. If you don't use the bypass, Be sure to use a Bellmouth on the tail pipe.

http://www.youtube.com/watch?v=H2moHwVW8NM

Joe Lewis
Kingtech
K-80 and K-140
Owner

flyboybuster

Hi modellbau, did you ever fly the jl f15 on the k80? I've been thinking of doing the same thing.

mikes68charger

My Feedback: (34)

I was thinking of buying the same plane to use with a pumped up 21-22 pound p80 and everything I read and got pm was it would be not very fun

snir2001

My Feedback: (1)

We have here a guy flying his SM F15 with P80se and it's just great (no doors and no bypass)
My JL F-15 fly perfectly with ATJ 120Ti (No bypass, but with full control and doors).

K80 is the minimum, P80 with 21~22 Lbs would be great, and the best choice is 120....