Take Off or Landing Performance

[P Johnson]

I am trying to work out which engine is right for me, my Kitfox SS7 should be with me hopefully in the next couple of weeks (left Kitfox 2 months ago), It will have Grove gear and 8.50 tyres an Airmaster prop with 70" Whirlwind blades, I also have a Rotax 912is firewall forward package coming with the kit so why am I still trying to work out which engine.
My airfield is at 377' and I will most probably not operate from any strip above 1500'. Landing performance is normally dependent on the weight of the aircraft and the pilot's skill but take off performance is more to do with the weight of the aircraft and the power the aircraft has but skill does play a part.
I have configured the aircraft to give me a good turn of speed and still operate off the farm strips we have in the UK. With an SS7 configured as above and using my operating criteria and a half decent pilot what will be the shortest take off or landing or another way of asking if you can get in can you get out, obstacles not included.

You know the Question.

[P Johnson]

I am trying to work out which engine is right for me, my Kitfox SS7 should be with me hopefully in the new year (left Kitfox over 2 months ago), It will have Grove gear, 8.50 tyres and an Airmaster 70" prop with Whirlwind blades, I also have a Rotax 912is firewall forward package coming with the kit so why am I still trying to work out which engine.


My airfield is at 377' and I will most probably not operate from any strip above 1500'. Landing performance is normally dependent on the weight of the aircraft and the pilot's skill, take off performance is more to do with the power the aircraft engine can achieve combined with the weight of the aircraft but skill does play a part.


I have been planning to configure my SS7 with Rotax 912is and the 70" Airmaster, I have gathered from others that this will give an efficient air speed for the airframe cruising below an altitude of 5000' which is what I will do most of the time and still operate off the farm strips we have in the UK.


With an SS7 configured as above and using my operating criteria I would like my take off distance be shorter or equal to my landing distance disregarding obstacles.


As I do not take off or land at high density altitudes and higher power will not give much higher cruise speed will the above combination meet my goals or should I start contemplating a Rotax 914 with aftermarket EFI?

[DesertFox4]

You should do great with the 912is. I operate in Arizona with a 912 uls “carburetors” and have mountains in every direction and have no issues. Had mine to 14,000’ and still climbing 500 feet a minute performance. I fly off short desert strips all the time.
I will soon be based at Sedona,AZ with an airport elevation of 4,831 feet above sea level. My Kitfox does great off that airfield.👍

[P Johnson]

You should do great with the 912is. I operate in Arizona with a 912 uls “carburetors” and have mountains in every direction and have no issues. Had mine to 14,000’ and still climbing 500 feet a minute performance. I fly off short desert strips all the time.
I will soon be based at Sedona,AZ with an airport elevation of 4,831 feet above sea level. My Kitfox does great off that airfield.👍
DesertFox4 thanks for the reply. What propeller are you using and what would you consider limiting, take off or landing?

[Shadowrider]

“I wish I had less horsepower” said no one ever! With that being said a turbo is not for everyone. They add more complexity and more maintenance, but significantly add to fun factor IMO. Added HP can add a bit of saftey also. Being able to takeoff short and climb above terrain gets you out of the danger area quicker. Having reserve power is always a good thing. I love my edge performance 9212STI but it’s not for everyone. 915 is a good option if you want more of a turn key package. Edge performance 914 is also a good option if you want a stock 914 with efi. I am not a fan of the rotax 914. I would go 912is before going that engine.

[3kdscf]

“I wish I had less horsepower” said no one ever!

So true! I have a Series 6 with a 912ULS and although its fine for 95% of what I need, flying over the Sierra Nevadas or the Rockies safely takes a lot of work. At 10,000 feet I only have about 200fpm climb at 1350lbs. When I hit TBO, I will replace with a 915.

[trond]

I have a 80 hp UL in my Apollofox and have found it to be more than enough performance for short fields at sea level. I have pitched prop for 5400 static and 5900 straight and level, for take off performance. Cruise speed at 5300 is 85, but at 10' feet I need to set flaps almost. I usually never go above 9. Too cold up there

[Danilo]

Where do you fly out of? I'm building a model 7 here in Lodi, CA (1O3) with a 912ULS, I'd love to check out your build if you don't mind.


So true! I have a Series 6 with a 912ULS and although its fine for 95% of what I need, flying over the Sierra Nevadas or the Rockies safely takes a lot of work. At 10,000 feet I only have about 200fpm climb at 1350lbs. When I hit TBO, I will replace with a 915.