Hello Fellows.
I am putting together an airplane somebody sold me that was built from kit. I am not sure of the name of it but thats not a question.The one i am wondering about is why does it have a downthrust in engine mount.I always though it should be just a 'few' degrees but when i snapped engine on ,OMG it looked like it was 30degrees from horizontal.Well,maybe not that bad but quite noticable.Here's a pic of it.Please let me know if i should get another mount or shall i use it as it is?
Also,what will change if i will mount engine paralel to the wing?

Appears to be an Ace Wizard. Down thrust is normally used in most highwing cabin types with a low thrustline to minimise pitch trim changes with power changes. That is quite a lot but suspect it is in fact what was intended. changing to another engine mount will not change the downthrust. That downthrust is built into the firewall. That engine appears to be over sized for this little trainer. What size is it and do you have the carburator?

I have a .50 size and yeah i have a carburetor for it ,it's just havent pu together yet.It's a brandnew sk .Carburetor is still in the bag.
Thanks for the info JohnBuckner

Yes, on most planes downthrust is required to make it fly half way decent. High wings require more downthrust than others. some mid wing and low wing planes can get by with very little. You will also need about 3 to 5 degrees right thrust on your particular model.

I had never seen so much downthrust on any plane. Been flying for 18 years now.......

Almost all trainer type aircraft have that must down thrust. Unfortunately that is very normal and must be that way. I have seen some that were worse looking that that and flew great. It's not a scale airplane, don't worry about it, just go fly and have fun!!!. [8D]

OK now we are getting somewhere now I am guessing and please correct me if I am wrong. If the airplane is what I suspect it does not have ailerons and has a wingspan of a about 45 to 55 inchs. This airplane was intended for engine in the .15, .20 class and certainly no more than .25. A Fifty, any relatively modern fifty is serious overkill and will not provide you with the nice trainer that is perhaps needed. It is going to be so nose heavy with that long nose moment that it will be difficult to get the CG where it needs to be.

The reason for the substancial down thrust is this airplane originated in the sixtys when single channel rudder only systems were the norm. No elevator! so the substancial stabilizer negative incidence in concert with the downthrust provide considerable pitch stability for rudder only flight.

John

The airplane is about little bigger then a 40 size trainer.Th wing is semi-symetrical with alierons that have individual servos.I honestly don't think that wing is from this airplane although it fits perfect.But guy who sold it to me told me it was flown with supertigre 61,so i think 50 should be okay.Also i found that it says WHIZ40 on the side.I never paied atention to it but now it makes sence.
I was worried about down trust but since you guys say it's okay i think i will give it a try.Will have to break in my new engine ...Also i thinking of setting alierons on different chanels.Thats gonna be my first plane with flaps.Interesting.
Overall plane seems to be in a good shape so i hope it'll be more fun then spad trainer.
Thanks for the input,folks.
I really appreciate it.

Mitty

Theres your idenity answer the forty size wizard. The Wizards have been around a long time in many variations kinda like the Sig Cadet series. So disregard what I said about he engine size. If it were me I would go with the downthrust. If the wing is something else, likely if it has flaps or added by some one, I would not bother with the flaps, will likely do very little for this airplane except make the possibility of stalling on a too slow approach more real.

John