AMB

I AGREE WITH John on the props not impressed with MAS also the wide blades of the grey graupner which is also stiffer less flex or wood zingers very good choices MAS does have a new "k" series wide blade but have never used one they are touting them for 4 strks
might be a diesel choice martin

Ldalmas

but how come the ma 12X 8 gave me about 8oz mor thrust?

DarZeelon

Lawrence,


...It was because your engine was spinning it faster and when pitch flattens out, more of the prop blade is in a lifting angle of attack.

In actual flight as more speed is attained, it is not the flexing of the prop, but the general design.

Your plane will will accelerate faster from the line, but will fly less impressively.
You can actually see this.


I still think the RPM (and calculated HP) numbers you are getting are pretty low, for what is supposed to be a quality, .40 BB, Schneurle ported engine.

Ldalmas

I know 40 irvine is not an inpresive engine as to what is power the ports and carb are pretty small. the 40fp which i have tryed is almost as powerfull as it from the tests i had made and the 40 fp i have tryed is abit worn out. now i have an mds 40 and i will see what will happen.

AMB

Ok guys just to refresh my memory I re-ran my irvine 40 diesel today graupner 12x6 grey prop it does have the muffler from an MVVS 40 on it, the smaller one single chamber no internal baffle, not really too noisey either 9400 Davic abc mix idle 2200 it it running muffler pressure to the tank no bogs on rpm pick up martin

mmuntner

Your disgust with the use of "small" props on diesels is interesting-but: it all depends on the airplane. That 9x8 prop would be OK loadwise on a Glow .40, so surely qualifies as a good choice for a .25 Diesel. However, why not a 10x6 prop on a .25 Diesel for an 80 MPH propwash instead of the 100 MPH of the 9x8?

The very big props which are often preferred by many are OK too, since operating under static conditions lower than the torque peak will really allow the beast to unload in the air; just don't expect a WHOLE lot of vertical performance at stall conditions.

I expect a great spate of disagreement with my remarks, but wottheheck, this IS a forum, ain't it?

Ldalmas

so that i can not get these results it is something in the fuel that i am useing but unlukily i can't purchace davis diesel fuel hear in malta

AMB

Your numbers are not that far off maybe the fuel you are only down about 400 or 500rpm but still pretty fair numbers martin

Ldalmas

500 rpm is quite a alot in power figures thats about 10-15% less power on a diesel (out of 9000) but i would still would like to test some davis fuel i think i should get better results should i try to add nitro to my mixture in a small percentage?

AMB

Can you get model technics fuel there from the uk?? martin

Hobbsy

My Feedback: (102)

I started to break in this Irvine Q40 today, it had zero pinch at the top but has excellent compression. I used a 12x6 three blade which it turns at 9,300 peaked and idles at 2,060. I think I'll put about 8 more oz of 5% Fox through it then put the Diesel head on.

Ldalmas

there is a hoby store nearme that has model thechnics 1000 but he sells it a bit expensive about 6$ for a half liter i think it is a bit expensive, he also has the last 40 diesel and he whants 150$ for it, what do you think is it worth?

AMB

Even if the model technics fuel is quite expensive I would try it for comparsion at least you will have standard to compare to $6-$7 litre would be more in line As far as $150 for the engine that was the list price when it came out, my local hobby shop had one one the shelf for years and I offered $125 which he sold it for that, then again if you pick up a Q40 and convert it you will spend that much anyhow or a little more Its really a judgement call on your part my thought is pro rating the cost over the years of life of the engine
it is worth it martin

SGC

Us Aussies pay A$12-15/ liter just for ether, we see you diesel fuel prices n wish we could import it(
Stewart

Ldalmas

half a liter is not much you can't do alot with it. as regarding for the engine i asked because you do not know what price is worth and what is not. and the guy who sells them is not of the very "frendly" we consider him a bit of a ************ so i whanted to know if what he asks makes sense

Ldalmas

as regarding ether i buy it for 30$ per 2.5l and it comes in a very fancy glass bottel

DarZeelon

I buy CP grade for $9 per 1.25 litre.

Technical grade diethyl-ether is about $6 per litre, but my MVVS/AJC Diesel apparently can't stand the taste...

Ldalmas

i tryed model technics fuel but i still got the same result it will not go more than 8900[]
i tryed in flyng and as idel goes i did not see any diffarance
Laurence

AMB

One more thing on the Irvine 40 diesel, I called JE regarding parts and they are going to try and buy all the spares (or at least whats left) from Irvine before
they become scattered all over the place or worse discarded since Irvine is now going overseas on production of the irvine engine line
martin

AMB

Just for kicks I reran my irvine 40 (not the Q40) this one required a custom head that AJ made since it not the same dimension as the irvine 40 diesel
or Q40 (same base engine) graupner 12x6 Davis ABC mix 9100 the engine is the older natural finish and predates the MARKlll maroon ones martin

Ldalmas

thanks 9100 is nearer my limits , i am now trying out zinger fiber props and they seem quite good they are quite stiff,

Iwould like to ask a few more questions; some times on some throttle settings the engine makes a funny banging noise an old guy sad it is the counter piston banging and it is normal?
and when I the engin ides it starts ideling well then it dies out after a few seconds as if the engine cools i tryed diferent settings but it is in vain

Hobbsy

My Feedback: (102)

L, that banging you hear and engine dying after idling a few seconds are both caused by the low speed mixture being a little too rich or from the compression being set a little too low.

Ldalmas

i have solved it now you where right it was caused buy a rich mix but due to a leaky carb

thanks

Ldalmas

i fitted a tuned pipe without the tuning cone to increse the cubic capacity of the silenser and ahhh finaly yes it whent up to about 9300 steady.
it seems the silencer is a bit small for it. the q 40 silencer is much bigger
Laurence

AMB

I run run the smaller mvvs 40-49 on one of my irvine 40s not the long one it does fine in the Mid 9Ks non baffled martin