Banksy

OK, Anyone else got a tacho reading for the irvine 39 yet?

Did mine today,

10x6 nylon prop, 5% model technics fuel, running a little rich, and throttle still has a few mm to open (not enough servo travel). Standard exhaust/silencer/muffler.

13,300 RPM.

It feels *very* strong on a 40 size trainer...

This is about right?

Si.

Banksy

Same as above, but with a 11x6 APC = 11200...

Not as fast, but nice; smooth and quiet, but plenty of acceleration.

I think somewhere in between 10x6 /11x6 would be about right.

Gav B

Anyone tried this engine with a 11x4 or 12x4 zinger or equivalent.

Banksy

I've got an APC 11x4 I'm going to try next, I'll post the results in the next few days.

tiggerinmk

Your 13,300 on the 10x6 is about right.....

I managed the same on Omega 5% (semi synthetic) fuel...
I tuned the engine to 13,000 for actual flight.

I got 13,600 on 15% fuel when the engine was new, it prbably still needs a bit of running in.

I'd be interested to see if this engine can turn the APC 12.25x3.75

Banksy

Tiggerinva,

What would be the advantage of a 12.25x3.75?

I've got an 11x4 to try, but I'm fairly new to this, so I'm using trial and error.

tiggerinmk

I just yanked my Irvine 39 out of my LT-40 trainer, I'm putting an OS 46FX to test/run in, so the Irvine is going spare right now.

I've just got a Magic Extra 300L which will either get the FX or the Irvine (or maybe even an Irvine 53 ).

The APC 12.25x3.75 prop is a favourite amongst the 3D crowd. I think the theory is that the large diameter gives good thrust while the fine pitch gives more control in a hover. This size prop is also designed for .46 sized engines.

Someone correct me if I'm wrong!

Banksy

gotcha...

The irvine 53 is supposed to be a great engine.

Let us know how the FX compares to the 39,

and have fun with the extra.

I'm wondering if my irvine 39 will power the seagull Pilatus PC-9.

There's one in my local model shop tempting me...

tiggerinmk

Here ya go, 46LA vs 46FX]

Banksy

So the irvine 39 is more powerful than the 46LA, but not quite as powerful as the 46FX.

One of the reasons I paid the extra for the irvine was so I could hopefully use it in my second plane, looks like that might be feasible now.

Cool.

tiggerinmk

The Irvine is more powerful than the 46LA using a 10x6 prop.

To get the full picture, I'd have to run the 46FX on a 10x6 and the Irvine on a 11x6. I'd expect the larger engine to be able to turn a larger prop with less of a drop in RPM due to the larger amount of torque available.

I do recall putting a 10x7 APC on the Irvine and seeing a large drop in RPM but I don't remember the actual figure..

I just noticed that you ran the APC 11x6, but I'd have to check and see if I get close to the same figure. Bear in mind, I used 10% nitro in last night's test.

With only 500rpm difference between the Irvine 39 and the OS46FX, it makes me wonder how the OS would fare against the Irvine 46...

Rob Roy

Irvine 39 fitted with a Weston UK Mini Pipe, APC 11 x 4 propeller 10% nitro = 14,250rpm

This specification in fun fly gives unimited vertical performance and good speed. However throttleability is slow, so prop hanging is a no no.

This rpm is comparable to that achieved by a 53 with standard exhaust

Stoneweapon

20% castor 80% Methanol:

8x7 APC 17200

10x6 Master Airscrew 12800



10% nitro 17% molsyn150:

8x7 APC 18300


Stockmuffler (very loud)

buzzard bait

Thanks for the data. I saw a magazine review that gave absolutely astounding figures--14,000 on a 10x6, 12,700 on an 11x5, and 12,200 on an 11x6. Those were all APCs; I didn't make note of the fuel, but it was definitely done with the stock muffler. I still can't understand how the rpms could be so high. The figures here seem much more realistic. Even so, it's an amazing engine for its size and weight. In fact, it's about the same weight as a Norvel 40AX; I can't remember the rpms I saw for the Norvel, but I don't think they came very close to this.

I bought one recently (the Irvine 39, that is) and it's such a beautiful piece of machinery I can hardly bear to put it in a plane. I expect mine will eventually go in a GP Rapture or a Sig Kougar.

Jim

Stoneweapon

Update with different Muffler for fun-fly application.

Muffler: Stueckerjuergen Funfly stainless steel muffler for 46 - 50 engines (very silent and pleasent noise)

APC 12x4 Sport 10800 RPM (without Nitro the throttle response is a little touchy but with 10% nitro no problems)


APC 12.25x3.75 11200 RPM (very smooth trottling)

Edit: All readings with FAI Fuel 20% castor, 80% methanol.

The Engine will not turn much over 13000 with this muffler because it is optimized for fun fly and the typical funfly props and their rpm-range.

Especially for fun fly models, which are operated near to the flying field noise reduction should be an issue. I like this muffler (it is lighter than the stock muffler even if made of stainless steel).

nicohaas

12.300 rpm with a APC 11*7 on a q500 5 % nitro standart fuel and the original two chamber muffler.
Here in Holland everybody uses this combination for slow quicky 80 dBA on 7 mtr

speed lover

I just got a new irvine 39 to replace my leo 37 and from what I hear on this thread it seems the right choice. My leo turned an 8x8 apc on 10% nitro and a Model technics F5 plug at 15,900 to 16,000 rpm but throttling was terrible I tried 4 different fuels the whole Model Technics Firepower plug range and also shimmed it but it would not throttle reliably terrible engine but powerfull flat out. Also tried a bibore carb 8mm got even higher rpm but just as bad at throttlig. Does the Irvine have a reliable idle and smooth throttling? I am putting it in a scratch built 25 size BAE hawk weighs around 3 1/4 lbs. Plan was from RCME Tony nijhius I think that's how you spell it originally had an O.S 25 SF in it but lacked the power for tight turn after tight turn. The Leo was great great power and light at 380g so balancing was easy hope this leo is good.

nicohaas

Sorry, I reported 12.300 rpm with a APC 11*7 but I mentioned 10*7
The Irvine 39 throtles very reliable en low. Also it is e very light engine.
I can advise you this engine.

nicohaas

bad luck , this new motor has an bad bearing on the cranckshaft at the backsite. The statical rpm does not exceed 11000 rpm.
The bearing was damaged very bad, metal part came in the liner, it has stripes now. The bearing is underdimensioned (13*42). It is replaced by Rob Metkemeier with a 2,5 cc teamrace motor.

buzzard bait

Just broke in on 10% nitro, 20% oil (1/2 castor) and after two tanks got the following:

MA 10x6 13,400
MA 11x5 12,500
MA K 12x4 11,000

Zinger 10x6 11,300
Z Pro 11x4 12,150
Old TF 11x4 12,250
APC 11x4 12,350

Don’t know why the Zinger 10x6 ran so slow. It was very old, don’t know if their design has changed. Note the Zinger Pro 11x4 did much better even though it should have loaded the engine roughly the same. I’m going to start with the MA 11x5 and then try the 11x4s.

Idle was amazing...2000 rpm on most props, and you could go even a little lower. 2100 was reliable on any prop. Throttle response was good after I got the low speed needle properly adjusted, which took awhile. I went quite a bit leaner than the factory setting.

Yes, it's loud with the stock muffler. I'd love to have one of those German mufflers.

Jim

buzzard bait

I think what it shows is that this engine is not optimized for big props. It will swing them and the throttle will work just fine, even with a 12x4, but you lose a lot of power...the drop off with each inch of diameter is greater than it is for many other engines.

I suspect even dropping down to a 10x5 might be best for some applications. Too bad it's so noisy on the smaller props.

Jim

buzzard bait

After flying the engine and putting about 3 more tanks through it, and using fresh fuel, I'm now getting 13,000 on the 11x5 MA. That's a gain of 600 rpm. Fuel is still 10%; humidity is in the 80s, it started raining after this test. I'm not sure the MA is a good prop at that rpm.

Anyone else get a significant improvement after some running?

Also, has anyone experimented with glow plugs? Mine came with a no-name idle bar plug, of all things. I'm getting a slightly sluggish throttle pick up, and thinking it might do better with a hotter plug. I could lean out the low speed idle some more, but I think it's pretty close.

Jim

nicohaas

I use rossi glowplugs (r3) no problems, you can do a long time with it, and you can't get better readings with another plug.
I use standart fuel 5% nitro. I have a lot of houres with these motors ( I have two) without problems. They are also al the same not much differans in performance. I start them bij hand.

buzzard bait

Thanks, I'll look into that. I start mine by hand too. One other issue...do you use a gasket between the muffler and crankcase exhaust? Mine leaks there and must vibrate...it spits dark grey oil.

Jim

nicohaas

Yes I use a gasket, it runs very clean.