tiggerinmk

I've just got a new Morvel .074 and was surprised to see the figures I was getting when I tached it during break in this afternoon.

Fuel: SIG Champion 10% nitro semi synthetic
Prop: Master Airscrew 7x4

AP .09: Struggles to get past 14,000 rpm. Highest recorded reading was 14,300 rpm

Norvel .074: Easily got up to 14,700 rpm. This in the first few runs of the engine...

Not bad for an engine half the weight...

kev71h

Really? DOes the norvel have bearings also? NOT bad if it does.

14,700rpm WIth the same 7x4 propeller???

So, this makes the AP hornet not that powerful...expecially for a higher displacement motor (?)

tiggerinmk

This engine is for a HOB Mustang kit. I've been a bit lax on this and not finished the kit, so I can't give more feedback on the engine performance. I can't see any bearings in the exploded diagram, but then the AP does seem to have a reputation for not being very powerful.
The specs say 3,500-17,500rpm on an APC 7x3. I've got that prop, so when I've got the Mustang finished I'll get some more figures...

FrancisPerson

14,000 on a black master airscrew 7x4 prop is the top reading that I get from my MP Jet .061 Diesel r/c. It weighs 3.5 oz, BB and twin needle carb. A bit heavy for its displacement but built very solid.

Francis

AMB

Francis does your MP jet 061D leak fuel at front bearing? I get similar numbers
but throw fuel thru the font bearing????

FrancisPerson

There is oil all over the place. I have not taken the time to figure out from where.

Francis

DesignMan

I have also had serious oil throwing problems with MP-Jet engines. For all that, though, they are solid and powerful. Currently one diesel is in a 245sq.in. replica of the Midwest profile P-51 CL kit. Does the full pattern with ease.