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Apr 26, 2019, 10:30 PM
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I could use a crank and prop drive plate and spinner nut ,I have one to convert
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Apr 26, 2019, 11:03 PM
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Quote:
Originally Posted by toad007
I did the very same thing but stayed away from the pull start version. I didn't want to modify the back plates from those. I have not flown a control line for at least 25 yrs. I am sure I am going to have to go at it slowly, I doubt I can spin that fast. About hoarding, I know a few guys sitting on dozens of them, one guy has over 70, rotting in a box! He wont sell any of them yet. I have no clue why I am so obsessed by this engine. So I want to start using them.
I have 4 engines left to modify, I think that will be all I need.
I have too many motors already. I wish I had more of the Piccos for the deal. 70 is just greedy. Part of a retirement savings plan I suppose. I have to laugh/feel sorry for some of the guys that buy motors for $30 and try to sell them for $100. It just is so much hassle, unless you have 1000 of course. I know guys that never saw the money. The grandkids had to go to the swap meets to cash in. I guess that is maybe an OK way to get them involved?
Apr 27, 2019, 12:36 AM
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surfer_kris's Avatar
Quote:
Originally Posted by Dave Campbell
like those similarly flawed VA .020ís
There is nothing wrong with the VA .020 ?
On the contrary, they are great and run a little stronger than a CoxTD .020 engine.
Apr 27, 2019, 03:05 PM
ffkiwi
Quote:
Originally Posted by surfer_kris
There is nothing wrong with the VA .020 ?
On the contrary, they are great and run a little stronger than a CoxTD .020 engine.
Not in standard ex-factory form they don't-not by a long shot! very disappointing-but in diesel form they seem to have more potential....

ChrisM
'ffkiwi'
Apr 27, 2019, 03:45 PM
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Quote:
Originally Posted by ffkiwi
Not in standard ex-factory form they don't-not by a long shot! very disappointing-but in diesel form they seem to have more potential....

ChrisM
'ffkiwi'
The gentleman I bought mine from in England explained to me that they were designed first for an .020 payload event in the USA. I donít know if that was supposed be a glow or Diesel event but given how few here like the little oil-boilers, I suspect they were initially glow motors that didnít get fully developed. With a stack of parts laying around it probably made sense to whip up some diesel heads in order to flog what had been made. I currently have 3 glow versions and one factory Diesel, I think if there were demand, Gkamysz could be talked into doing a run of o-ring Diesel heads. Performance as a Diesel is about where you would expect it to be-they seem much more tolerant of porting shenanigans.
Apr 27, 2019, 04:00 PM
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surfer_kris's Avatar
Well, from my experience they are great engines (I have two of the glow version). I got one faulty glow head (small leak around the insulator) but I simply made a Turbo plug head instead and I love them. I have also made an RC carb (from scratch) and they throttle alright too, even if they do have quite a lot of SPI.

With the RC carb and a DIY muffler, I'm getting about 19700rpm on the grey Cox 4.5x2 prop (using 10% nitro fuel) that beats the TD .020 by a hefty margin (from memory the TD will do around 18000rpm on the same prop, and that is without any muffler).

Here is a short bench run:

VA .020 with RC carb (0 min 53 sec)
Apr 27, 2019, 09:34 PM
ffkiwi
Mine came from Dave Banks in the UK...on 30% nitro and a Cox 4.5x2 in bog standard form (ie as it came out of the box) the best it would do was 16,700 on that prop-about 3000rpm down on a good TD 020 [I may only have 1 VA 020-but I have over a dozen TDs-and I know what a good, average, or outstanding one will do without any reworking done.]

ChrisM
'ffkiwi'
Apr 28, 2019, 02:09 AM
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surfer_kris's Avatar
It is funny how different experiences one can have.

The TD .020 will not very run well on 10% nitro, the compression is too low. It can be improved by removing some material from the glow head (in a lathe) but haven't written down any rpm number from those trials.

The stock VA head might simply need som shaving off as well in order to increase the compression ratio. I didn't want to play around with those as I only have the ones that came with my two engines.

The VA also came with two different venturi intake diameters, on the smaller one I got 18800rpm while the larger one seemed to need fuel pressure in order to run well, and I didn't take a tach reading on it.
Apr 28, 2019, 06:57 AM
Registered User
The reports on RCU when it came out were that it put out the same numbers as a Pee Wee, so I think you got a good one.
Apr 28, 2019, 09:02 AM
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surfer_kris's Avatar
In that case I would guess that it is mainly a compression ratio issue (piston height at TDC in combination with the head volume). I haven't been able to take mine appart (cannot slip the conrod off from the crankpin) but from what I've understood the conrod and piston has a similar construction as in the VA .049 MkI engine, i.e. the piston height at TDC is adjustable. So perhaps mine engine has the piston a little higher than others, it certainly has quite a lot of SPI.
Apr 28, 2019, 05:17 PM
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toad007's Avatar
Thread OP
I have the cranks heat treated now. This week is looking up. Just a comment here. I have a Cox/Rossi .15 with a tremendous amount of SPI. and a perry carb on it. It throttles crisply and idles great...Kinda makes a guy re think all the SPI hype, at least it did me.
Last edited by toad007; Apr 28, 2019 at 05:24 PM. Reason: added comment
Apr 28, 2019, 05:31 PM
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toad007's Avatar
Thread OP
On another view of SPI, Back when Estes had the cox line The racers sought those cyl's that had a lot of spi and needed 4-5 head gaskets to clear the head at TDC, We shimmed the cyl up to where we had 0 spi , then we could reduce the head gaskets back to one or two and we had a very hot contender then. Note, 0 spi. go figure. I still have a TD or two setup like that. We ran very high nitro content fuel in them, 40-70% nitro and they held together.
May 01, 2019, 07:00 PM
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toad007's Avatar
Thread OP
I ran a crank today, It didn't break, I got 31k steady with no venturi, open exhaust on the 4.6x3 red
fuel was 25%. I think I can compress it more. the next few days will be fun. I will get some video. I like it so far, I hope I dont break it.
I am going to try a bit less dia and a bit more pitch. I should set it up on 10% I need to get some mixed or buy that Sig fuel the c/l guys use.
May 01, 2019, 07:27 PM
Registered User
Great news! 31k on that prop is some power....
May 01, 2019, 08:17 PM
Nitro User
1/2A Nut's Avatar
31k / 4.6x3 / 19.4oz thrust / .288hp - 215w / 88 mph pitch speed.
I bet it was loud, did you use earplugs?

The APC 4.4x4 cheap and plenty on tap for flying days.
If 29.7k / 15oz thrust / .282hp - 210w / 112 mph pitch speed
Last edited by 1/2A Nut; May 01, 2019 at 08:27 PM.


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