MJD

My Feedback: (1)

Finally I got around to test running this engine, and wanted to pass along what I've observed so far. Yeah I know they're not available anymore (curses..) but there must be a few out there.

Conditions: frikkin' cold, about 20F, and windy. Hiding on the deck to stay warm but determined to run the darn thing.

Fuel: Cox Super Power fuel, because I had a couple of new cans and it seemed a good choice for break in runs.

Prop: 5-3 Cox rubber ducky (black) because I haven't made APC prop bushings for it yet and this is the only one that fit the prop screw snugly for centering.

Plug: Nelson HD

First run - running in a rich two cycle, 17,800 - 18,000.

Second run - a bit leaner, 18,500 - ish. Throttled down to 9k fairly reliably, transition a bit rich and stumbly as expected, I haven't tweaked the air bleed yet either, need a few more runs before I feel compelled to do so. Setting seems close though.

Third run - running steady and happily at 19,200 or so. Peaked at 19,800 for a couple of seconds then I backed off again. throttling improved a bit.

Fourth run - similar, kept it at 19,300 or so, a couple of quick excursions to flat out at 19,800- 19,900. Motor richened up fine after peaking, back to 19,200-19,300 and steady.

Fifth run - screw this, my hands are freezing. Another time!

Engine still has squeeze at TDC, so seems I haven't wrecked it yet..

So far I like it. A bit heavier than the AME 061, but seems to have pretty nice manners. Start easily by hand, easier with 1/2A electric starter of course (Speed 600 with prop adapter, push button and rubber hose drive cup, on 12V spins the motor plenty fast!). Due to air temps hand starting cold was a bit stubborn.

Does anyone have comparable data for an AME .061 ot TeeDee or? Yeah I know a FORA will spin the blades off..

MJD

BMatthews

That sounds very similar to my own results when I ran mine a season or two back. I was running with an RC carb that I got from Larry. But as he warned the air bleed not being adjustable made for a very poor idle. However it started easily and ran strong with about the same numbers as you on my 5x3 Cox grey (if I remember rightly).

I was running the VA back to back with a Medallion RC engine and was delighted at the easy and nice idle of the Medallion. I came to the conclusion given the problems with the VA muffler (stupid spring clip) and issues with the carb and from the relative ease of idle and transition with the Medallion that I was going to try making a new muffer with an integral exhaust valve for the VA and combine that with a moderatley long fixed opening suction venturi instead of the carb.

However like many of my projects.........

SGC

Heres some No's I saved that from memory CP posted,
COX TD049
5x3 COX 22,000
6x3 MAS 16,000
5.7x3 APC 20,000
5.5x2 APC 21,500



AP
5x3 COX 20,000
6x3 MAS 16,300
5.7x3 APC 19,200
5.5x2 APC 22,500

AME
5x3 COX 21,200
6x3 MAS 17,900
5.7x3 APC 21,200
5.5x2 APC 24,000

BigMig is about - 1,000RPM from the AME
My own Bigmig 061 clocked 18,700RPM on a MAS 6x3.5 cut to 5 1/4" an 24%Castor,20% Nitro fuel.
Stewart

combatpigg

My Feedback: (3)

Stwart, your memory is better than mine! The results with these little engines is subject to this or that, MJD. Your results with the VA are good enough to go out and have a good time with, that's for sure. I would expect that it will continue to get stronger with time. I bet Larry gives them a flip or two before sending them out the door, just to make sure they feel right. You should see the VA run with a C/L venturi and a little combat prop! Time to get out the ear plugs!

On a very good day, a TD .049 can turn a 5x3 prop 24,000 rpm on 40% nitro. This was with the high compression KK head and a 5x3 prop that hadn't been checked for true pitch. The older those rubber props get, the more the blades flatten out with rpm. I have seen a new first generation AME turn the same prop over 25,000 rpm, but it couldn't turn the trick twice in a row without seizing up. A FORA .049 doesn't turn a 5x3 much better than this, but it does it so easily on sport fuel. To wake up a Fora, you got to get rid of some prop diameter.

Comparing your carbureted VA to these WFO engines isn't fair, but I just want to let you know that if you ever want to see what your VA can do, don't be bashfull because it is just loafing at 20,000.

MJD

My Feedback: (1)

I also have a pair of VA 049 MkI's with venturis, these are the "roll your own timing" models. I have run one on the bench so far, with the pressure venturi, latex bladder, on 35% nitro and with an APC 5.5-2 clipped to about, oh, 4.75". Yeah, you're right - get out the ear plugs! It's not a Fora or Profi, but it is the strongest pulling 1/2A I have ever had my hands on. I plan to put these on SWR's this spring.

I believe there are a few more rpm to go yet, I can see it hitting 20k or maybe a hair more on the Cox fuel, once I get 3-4 more runs on it I'll go to 30-35% nitro and a 4.5-3.5 or 4.2-4 prop. I'd like to coax it up to the 23-24 k regime.

The muffler on this one is not spring mounted, it mounts with a pair of machine screws. I was running it muffled on these runs. probably a good idea at 10am on a Sunday morning in a small village of 12 houses and a church.

flyinrog

My Feedback: (1)

Mine is the .06 VA, its rear exhaust and the muffler screws on, havent fired it up yet,maybe this spring...Rog

MJD

My Feedback: (1)

VA .06?? Never heard of it. How come I don't have one? []

MJD

flyinrog

My Feedback: (1)

I think its 1cc? It does have a screw on rear muffler..I know my AME is .061, havent run it either though, or the CS .061, I confess I bought it just cause its purty.....Rog

AndyW

My Feedback: (1)

Keep in mind guys that all the VAs should be run with a castor based fuel. A blend is OK but the more castor the better in my experience. Otherwise, like Cox, if you don't, the rod will wear too fast at the piston end.

I'll be making up a proper, 1cc VA using Norvel parts some time this winter.

I have still new, never run, 5 of the VA MK1s. Three of these are nickle plated all over, inside and out. This is the way they did it at the very beginning.

These may have collector value but I went and trimmed off the intake to all of them to take throttles . Dang.

MJD

My Feedback: (1)

That's why I used Cox fuel for those first runs, as it definiteyl meets those criteria, and was the only suitable stuff in my shop at the time. Normally I'd used Sig Champion with an extra 2% castor, making it about a 51:49 cas/syn blend at 22% oil. That'll work fine, my Coxes seem to like the taste.

MJD

DeviousDave

The VA motors are timed a little too wild for a 5-3 prop. Need to go a lot smaller, with big hits of nitro.

AndyW

My Feedback: (1)

I can confirm that. My usual 6 X 3 black Tornado is not well tolerated. For general, RC, sport use, I like the APC 5.5 X 2.

MJD

My Feedback: (1)

Are you guys talking about the VA MKII R/C or the VA MkI / MkII combat motors? I have no idea if the R/C version has any variations to the timing from the C/L versions. The R/C version I'm running right now doesn't seem to mind the 5-3, but you may be right and I will soon find out, as next runs will be on 4.5" and 4.2" props and higher nitro. We'll see how much it goes nuts on those. I would never put a 6-3 on it, I know it ain't meant for that. But it was well mannered on the 5-3. That was the only prop in my arsenal last weekend that fit snugly on the prop screw, it's a bit smaller than a 5-40. I'm making some bushings for my APC props now. I don't use fuel tubing, under the compression of the prop screw I've seen it let the prop wander a bit. I prefer rigid bushings on 20k plus engines - I'm finicky in that regard.

MJD

AndyW

My Feedback: (1)

MJD,

I was referring to the MK1. My experience, (for sport flying anyway) is that the MK2 RC version does well on a 6 X 3 but the MK1 likes smaller props. Keep in mind, this is sport, RC.

But you also need to keep in mind that not all props are created equal even in the same size.

Look at a 6 X 3 in a Cox, a Tornado and an APC.

The first has huge blade area with a square tip. The Tornado, much less with a rounded tip. The APC is the dinky one with a knife like blade and a pointy tip.

The interesting thing is that on some applications, even though the Cox loads the engine more and reduces RPM, in the air it generates more thrust. That is one very efficient design. I wish it was available in all sizes up to gassers.

Also, it's been my experience that if the Cox 6 X 3 is too much load, better to go to the Tornado 6 X 3 to reduce load rather than a 5 X 3 Cox. Don't know why, despite the preceding, it just works that way, for me, for sport RC.

Another point. One feature of the Cox props is that the flat bottom airfoil is carried all the way to the hub. I've applied this feature to a variety of props from APC, the Tornados and some Taipans and in all cases, I get from 500 to 800 boost in rpm.

MJD

My Feedback: (1)

Gotcha. No, I'd never load those down. I ran my VA MKI on a 5.5-2 clipped to somewhere a bit under 5", maybe 4.7 or so (forget, I should check it), and on the large venturi and pressure with 35% nitro & 22% oil. It spun like mad, static thrust was more than I've ever encountered with a 1/2a. Definitely a FF setup with that prop. If'n I put one on a SWR or Blink it will run a 4.2-4 for starters and 35-40% nitro.

combatpigg

My Feedback: (3)

It seems to me that this engine would be a good one for a 1/2A 3D model. My prop of choice then would be the 6x2.