Mr Cox

I have been working on this for quite some time now and I had some rely nice flights this sunday. It might be the last one before the snow (only patches so far) and I just thought that I would share a few images. It is not quite finished yet but it is really close now, just need to put a few baffles inside the engine cowl. I have had wheels cowls on to but on the winter grass we have now I need a little larger wheels.

So with some really nice help from Andy, here it is, a Norvel .074, with low end adjustment on the carb, a built in starter spring and MP Jet spinner (drop in by replacing the stock M4 bolt with a pin bolt). Some of you may recognize the much desirable logo...

makoman1860

My Feedback: (1)

Very nice! Very clean firewall package.

combatpigg

My Feedback: (3)

Nice work Mr Cox! It does look like a "big" set up.

fit90

Mr Cox,

That whole plane looks fantastic but firewall forward (FWF) really gets my heart pounding.  Nice work.  Is the plane a kit, ARF or scratch built?  SWEET!

Bob

MJD

My Feedback: (1)

All it needs is a small dog named "Aileron" behind the pilot to be complete.

NICE work.

hllywdb

VERY nice work Mr Cox! Like the sticker too! Great attention to detail, cool in-cowl muffler.

How does the 74 like inverted? I had thought about that on my last build.

Bill

eroc144

My Feedback: (1)

Excellent! How about some pix of the low end carb adjustment doo-hickey?

EG

makoman1860

My Feedback: (1)

X2! I have done my own but always interested in someone elses work!

Mr Cox

The plane is an ARF from Carl Goldberg, and I don't think they make it anymore. But there is also one very similar from Hyperion that is still available.
I did a conversion thread on this about a year ago, and it can be found [link=http://www.rcuniverse.com/forum/m_9052204/anchors_9052204/mpage_1/key_/anchor/tm.htm#9052204]Here.[/link]

The plane always flew well but to just have one needle on an engine is plain silly, and I had to compromise the high end to get a good low end or vice versa.
Andy has been very kind and he sent me a carb with the added airbleed screw to it. It is very limited space there and a it does require a proper setup. I've then blocked the airbleed slot from Norvel in order to make the airbleed really active. I'm very happy with the engine now. It will spin an APC 6.3x4 at 17500rpm, and the idle I have set to about 4-5000rpm to be a little safe. At 19oz (with a 750mAh battery against the firewall) it is actually a little bit overpowered but it is nice to have a bit of extra power in the uplines and stall turns. Half throttle is enough to fly around doing some cuban eights and it is then very quiet too.

I've never owned any electric starter, and have told a friend that I would never get one, so I had to sort that out somehow too...
The starter spring is the stock one from Norvel .061, just made a new trust plate that goes outside the stock one and the spring pushed very lightly against that. Two slots for grabbing the spring is enough and there is no sound from this when the engine is running.

eroc144

My Feedback: (1)

MC - Anything below 20oz is dynamite for an .074. I'd imagine the uplines are pretty strong. How'd you fill the stock airbleed slot - JB Weld? The cowl work looks great too, and what the heck is that muffler?

AndyW - When do you think you'll be offering air-bleed conversion services to the masses? ;^) What size holes did you drill for the air hole and adjustment screw, and what about the screw & tap?

EG

Mr Cox

JB weld everywhere, both in the carb slot and for making the "muffler"...

I have tried the new aluminium "solders" too but I couldn't get it to work well, just makes large bumps of material that are not fused to the rest. Guess I'm not scratching enough in the melt or something. I've made two mufflers with different resistance and muffler pressure. One with less resistance, a bit like the MVVS minipipes/mufflers, and that improves the top end while making more noise. The one in the picture is the quiet one and the engine runs very smooth with that one. Only problem is that I can't hear the engine if anyone else is in the air or just revving in the pits.

flyinrog

My Feedback: (1)

I got one of those the goldberg chipmonk arf, iirc it didnt come with the same crap motor the tiger did (put a norvel in it and it was a blast), and I was gonna go norvel, but had a brushless that fit, never have flown it, just sitting like all my other stuff....Rog

rrragmanliam

My Feedback: (1)

I have to admit that I never have had this problem with my .074 Norvel engines. I've just set the needle for max top end (with no lean out) , then go 1 click rich and it idles fine. The idle is low enough that a plane with gear will stand still on a paved runway. What else do ya need?

rrragman

Mr Cox

Well, if it was that simple then all engines would have just one needle, on much larger engines too. But we do not have that, since there are so many other variables, such as fuel selection and glow plug etc. OS are offering adjustable airbleed on the .15 and up, but not on their .10. The .10 carb is even identical to their .15 it is just that they cannot be bothered to drill and thread a hole.

To me there is nothing magical about the carb on the Norvel. There is a fixed airbleed slot, that fills the same purpose as a fixed airbleed hole does, and this is supposed to take care of the low end, and it that may well work for most people. I think on this particular carb the spray nozzle was offset or something giving a too rich low end. On another stock carb the low end would be too lean and so on. I cannot see any reason not to have an adjustable airbleed when it is so simple to put one in.

Call me picky if you like, but I cannot find any reason for not making a proper carb for the smaller sizes too, apart from a relatively small economical gain for the manufacturer.