Down Angle On Motor?
 

I just set my motor mount on my Hangar 9 Alpha 40 trainer. It's not the motor mount that came with it as it would not accommodate my motor so I picked up one at the hobby shop.
I noted that the firewall on this model slants as the top if further forward than the bottom so it matches the angle on the motor.
But when I mount my motor it looks pretty strange to see a down angle on the prop shaft.
I looked at the stock mount and I would have the same down angle if I used it.
Is this normal or did I miss something and I was supposed to shim? Or is there something I don't understand (again).

RE: Down Angle On Motor?
 

Most trainers have some down thrust.

Tom

RE: Down Angle On Motor?
 

yes thats called DOWN THRUST..It keeps the model from climbing under power..Perfectly normal for a high wing trainer

RE: Down Angle On Motor?
 

OK, I have had a lot of time between my last build of a trainer~over 30 years anyway.
I thought that the mount was supposed to replicate the angle on the firewall but it just seemed odd.

<font color="#00265e" size="2">mighty9</font> ~~I note you are in Pearce. I had property in Cochise County 10 miles S of Sierra Vista until a couple of years ago when we got out of the wind and hear and moved up here to Prescott. My wife was born in Tombstone a long time ago. She thinks she was one of the last kids born there at the hospital before they closed it in the late 40s or early 50s

RE: Down Angle On Motor?
 

Do a search here on RCU using thrust angle or engine thrust and you will find a lot of threads on it.

RE: Down Angle On Motor?
 

Small world isnt it.I have relatives up north as well. its nicer than here for sure. 10 miles south ? near hereford?

RE: Down Angle On Motor?
 

Well since were on the subject here in this thread, I'm converting a Pulse 25e to glow and have some questions about the thrust angle. The firewall is set at 2 down and 3 right, that seems excessive for a low wing plane. My Ultra sticks have zero right thrust in them. Does an electric powered plane have to have more down and right thrust than an glow plane? I'm not comfortable starting out with that much angle for my glow conversion. I'm mounting an OS 40LA in it by the way. Its an old engine that I had laying around and wanted to use.

RE: Down Angle On Motor?
 

You can probably experiement with it. One of the guys at our field was working with an electric and he simple could not get the plane to fly well until he got the angle right. After that, she was a pure joy.

I know on my Twist 40 (with glow) I had to get the engine angle right. I had drilled it off slightly and the plane just did not perform well. I had a hard time getting it trimmed out. I changed the angle and it is so much better. I never thought it would make so much difference.

You could probably shim behind the mount, or test with an alternate mount, and then once you get it were it works best, drill and mount with the same angles.

RE: Down Angle On Motor?
 

Scooter i did the same and good results converting an ep to 30 saito glow.Old rule of thumb re down and sidethrust is to look at the engine from the front mounted sans prop,note the crankshaft diameter say it's 8mm,thats the amount of side and downthrust you need..roughly:)

RE: Down Angle On Motor?
 

Trainers are designed to be speed sensitive. They are set up nose heavy, with a large amount of decalage and down thrust to compensate for the first two conditions. This setup causes it to climb with more speed and drops the climb rate as the speed bleds off. Once trimmed out, they more or less fly themselves if the beginner pilot has the sense to leave the controls alone. It also makes them a pain to fly as the skill level increases.

RE: Down Angle On Motor?
 

Yep, about a 1 south of the new Post Office on the highway at the base of the mountains. Lots of drugs and illegals there. So bad they posted this sign in the national forest~

RE: Down Angle On Motor?
 

Yea thats the feds idea of securing the borders here.......My son in law is a base firefighter they spend lots of time fighting and monitoring fires started by them in those mountains..I guess ive fully hijacked and ruined your thread .lol Cris

RE: Down Angle On Motor?
 

Nope, I got the answer I wanted in the beginning.
And others have jumped in to get answers to their questions that are related to mine too.
That's fine with me.

RE: Down Angle On Motor?
 

It is a sad state of affair's when you see signs like that. I was on the county fire department in Calif. just outside of Yosemite and was always out on call for brush fires started by the Hmongs that live in the valley. There hunting methods are a bit different then ours. When Squirrel hunting they would start a fire under a tree and get them moving with the smoke. Then they would just leave the fire burning and leave so when the wind kicked up it turned into a blaze. [>:]