OS 46 LA : Derek Pickard Article ?

[Robin_Holden]

Help please guys .......

Around 2003 Derek Pickard wrote a great article regarding the OS 46 LA for Stunt News.

Does anyone have a copy please ?

I'd be very much obliged if you could e-mail me a copy ?

my e-mail address is : robinchristine@msn.com


Very much obliged to anyone who can help , great forum as ever........

Kind regards from S.W.France ,

Robin [ ex-pat Brit in the Charente full of ex-pat Brits ].

[Andrew Tinsley]

Hi Robin,
  The article was republished in the Aeromodeller section of AMI. I should have the magazine, will search it out and email it to you this evening, unless someone beats me to it!
  The article tells you how to improve the stunt run by filing the top of the ports by maybe 15 to 20 thou and to angle the top of the ports upward. This is from a not very good memory! I don't know what folk here think of such mods? Mine seem to work very well indeed out of the box, never had a run away situation. Personally I feel there are better ways to improve the 4-2-4 break, than taking a swiss file to the ports, prop selection being one of the better ways IMHO. I run mine in a wet two and it just flies with plenty of power in the manoevers. Its just great, but not quite as good as the TT GP42, which seems to have a tad more power.

Regards,

Andrew.

[Paul Taylor]

Robin,
Why would you want to mess with it?

If it ani't broke, don't fix it.

[Bob Kruger]

Hi Robin,
  The article was republished in the Aeromodeller section of AMI. I should have the magazine, will search it out and email it to you this evening, unless someone beats me to it!
 Personally I feel there are better ways to improve the 4-2-4 break, than taking a swiss file to the ports, prop selection being one of the better ways IMHO. I run mine in a wet two and it just flies with plenty of power in the manoevers. Its just great, but not quite as good as the TT GP42, which seems to have a tad more power.

Regards,

Andrew.

Andrew;

Just curious, but what is your setup with the TT 42?

V/r

Bob

[Brett Buck]

 The article tells you how to improve the stunt run by filing the top of the ports by maybe 15 to 20 thou and to angle the top of the ports upward. This is from a not very good memory! I don't know what folk here think of such mods? Mine seem to work very well indeed out of the box, never had a run away situation.

   Correct you are!  Don't FILE anything on this engine, or any other. It doesn't need to be filed, ground, hacked with hand axes, etc. Not to mention it's awfully difficult to repeat the results with nothing but a file and a devil-may-care attitude.

   I have several epic diatribes  and/or quasi-psychotic rants on this topic here and on SSW, but these sort of mods are the classic "local expert" type garbage. And even if you succeed, you have still turned a Ferrari into a Yugo. 40FPs used to be the main target of this sort of thing (some, for good reason) but the effect is to kill the power. Now it's hard to get 40FPs, so now people have turned their efforts towards ruining 46LAs.

     Brett

[Jim Pollock]

These are the only mods I recommend for an LA .46

1.  Replace the plastic back plate with a metal one.  FP .40 Parts will work nicely
2.  move the needle valve and intake forward to the normal location.
3.  Ensure you keep the venturi size at .305 down to .260.  Obviously the larger one will need more fuel but will put out quite a bit more power than a ST .46 with correct proping.

Jim Pollock,  These are the only modifications I have done to mine!  Oh yeah, I'm using an FP .280 Venturi

[Balsa Butcher]

Jim: Are you using the OS needle valve and spray bar (smaller diameter?) or the STor Aero Products NVA? I only ask because I have one with the OS NVA up but am considering the switch to the more precise but larger diameter after market set-up. 

[Mark Scarborough]

The good LA 46 setups around here run between a .272 and .278 venturi with the Larger ST sized, or Aero Products (?) needle assembly. 12.25 x 3.75 APC and 10-22 fuel,,

[Balsa Butcher]

Thanks Mark, the ? next to Aero Products NVA was a typo, hate it when that happens...   I'll check my venturi diameter. 

[Bob Kruger]

These are the only mods I recommend for an LA .46

1.  Replace the plastic back plate with a metal one.  FP .40 Parts will work nicely
2.  move the needle valve and intake forward to the normal location.
3.  Ensure you keep the venturi size at .305 down to .260.  Obviously the larger one will need more fuel but will put out quite a bit more power than a ST .46 with correct proping.

Jim Pollock,  These are the only modifications I have done to mine!  Oh yeah, I'm using an FP .280 Venturi

Jim;

I am curious to the setup where the venturi gets up near .305.  All of mine are around .275-.280.  What have you seen at that size that runs well?

V/r

Bob

[Phil Coopy]

Lately I've been using a .282 homemade venturi with a ST NVA and a lower compression head (that Carl Shoup reccomended) running on 10/22 Powermaster.  I seems to work really well during those 95+ dayes here in FL....no runaways at all. I have not done any more experimentation with the LA46 tho since I shifted to a Stalker 46SE which I like very much.

Not making any reccommendations....just that this works better for me than the factory stock setup.

As an added question from an old performance engine builder: How can the LA40 and LA46 have identical cranks (i.e. counter weights) but have seriously diffent piston weights (reciprocating mass) and both be balanced accurately? I noticed this when I replaced an LA40 with an LA46.......much more vibration with the LA46.

Phil

[Robert Zambelli]

Brett - BEAUTIFULLY PUT!!!!!

"Correct you are!  Don't FILE anything on this engine, or any other. It doesn't need to be filed, ground, hacked with hand axes, etc. Not to mention it's awfully difficult to repeat the results with nothing but a file and a devil-may-care attitude.
   I have several epic diatribes  and/or quasi-psychotic rants on this topic here and on SSW, but these sort of mods are the classic "local expert" type garbage. And even if you succeed, you have still turned a Ferrari into a Yugo. 40FPs used to be the main target of this sort of thing (some, for good reason) but the effect is to kill the power. Now it's hard to get 40FPs, so now people have turned their efforts towards ruining 46LAs.
     Brett"
I wish more people would subscribe to this line of thinking, especially regarding the LA 46.
Sadly, many people believe that a stock engine just won't perform - they insist on, as you put it "filing, grinding, hacking, etc. They really don't understand what harm grinding through a plated interface can do.
The three best running FP 40s I've ever seen were used by Dan Banjock, Mike Palko and Jack Weston. They shared one common factor - all COMPLETELY STOCK.
As a side note, once Dan and I had an interesting conversation with a gent at Brodak's. He told us about his whiz-bang Fox 35. He installed every available gadget from the stuffer backplate, special crank, ABC setup, THE WORKS, to a total investment of around $240.00. When Dan addressed the pertinant question "How does it run, Rusty Brown replied "Darn near as good as a stock one!"
Bob Z.
Also, one fellow claims that the Brodak 40 MUST be reworked to succeed. And, succeed he did - in voiding the warranty.

[Robin_Holden]

Very much obliged fellas for all your contributions , thanks.

I'll leave well enough alone !

My 46LA runs just fine stock , so that's how it will stay.

Thanks all again ,

Robin.

[Andrew Tinsley]

Hi Bob,
  I don't have any special setup for the TT 42 GP. I just used the dimensions for the stock OS Venturi and NVA that you can buy from Towers (Think they are the stock FP40 and LA46 items). Not wanting to drill the crankcase, I milled and turned up a couple of bolt on Venturis, that replace the two screw, RC carb (a damn sight easier to use the SSW item and cross drill the case!!!). I then installed the stock OS NVA. As far as props go, I use the normal ones associated with the LA46. Other than that, I run it stock. No extra headshims or any other mod.
  I find it makes just that little more power than the LA46. It is a superbly easy starter, better than the LA46 if that is possible! The other two advantages are that it is more economical than the OS (around 15% less fuel for the pattern). The other plus point, is that it is far better engineered than the LA46. I believe that it is true ABC, it has a metal backplate and the crank is a much better item than the LA46. Let's face it, the LA46 has been designed down to a price and although it is adequate, it is by no means the best quality engine produced by OS!
  If it were not for the weird bolt on venturi, I think that this engine would be far more popular amongst stunt fliers. I have 3 LA46s and a couple of TT42GPs. I would not buy another LA46 as long as I can get TT42GPs, last time I looked at Towers the TT was cheaper than the LA in RC format.

Regards,

Andrew.

[Jim Pollock]

Well,

Some of the latter FP .40 venturi's were up to around .305.  Using bigger venturi's will increase power along with fuel consumption.  That's why I use the .280 venturi, it seems to work great and not be too much of a fuel Pig.

P.S.  I just use good old OS needle valves.  If I decide I need more mixture control, I would use one of Randy's needle valves.  Then I might go to a .290 or so venturi.

Jim Pollock

[Wayne Collier]

As a side note, once Dan and I had an interesting conversation with a gent at Brodak's. He told us about his whiz-bang Fox 35. He installed every available gadget from the stuffer backplate, special crank, ABC setup, THE WORKS, to a total investment of around $240.00. When Dan addressed the pertinant question "How does it run, Rusty Brown replied "Darn near as good as a stock one!"
Bob Z.

Still laughing, How many of us have lived that in a variety of life's situations.  Having read previous posts about Rusty Brown, I'm inclined to believe that he had a really good perspective on the topic at hand.

[john e. holliday]

You really had to know the gentleman.  I knew Rusty from my early years in modeling when he would come to KC to fly.  Like when I forgot the inverted portion of my pattern in a way.  I only did four laps.  Rusty asked if I still remember music class.  Then started,  go one-a, two-a, three-a and so on until you get to six.  You really missed a great person if you never met him.