News:



  • May 28, 2024, 04:49:13 PM

Login with username, password and session length

« previous next »
Pages: [1]   Go Down

Author Topic: LA40 to LA46 conversion?  (Read 2280 times)

Offline Andrew Tinsley

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1345
LA40 to LA46 conversion?
« on: April 17, 2014, 08:28:39 AM »
Hello,
I have an LA40 which doesn't seem to be nearly so well mannered as an LA46 for stunt. I assume both engines have the same stroke and that the LA46 P/L will drop in place of the LA40 P/L?
  If so is it just a simple conversion? I do not have a spare LA46 P/L to hand and I do not want to strip one down unnecessarily.

Regards,

Andrew.
Logged
BMFA Number 64862

Online Gerald Arana

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1537
Re: LA40 to LA46 conversion?
« Reply #1 on: April 17, 2014, 09:27:06 AM »
46 won't fit in the 40 CC.

Jerry
Logged

Offline Bill Little

  • 2017
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12671
  • Second in COMMAND
Re: LA40 to LA46 conversion?
« Reply #2 on: April 17, 2014, 10:22:17 AM »
But, AFAIK, the .46LA will drop right in place of the .40LA..... ;D

BIG Bear
RNMM/AMM
Logged
Big Bear <><

Aberdeen, NC

James Hylton Motorsports/NASCAR/ARCA

AMA 95351 (got one of my old numbers back! ;D )

Trying to get by

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12823
Re: LA40 to LA46 conversion?
« Reply #3 on: April 17, 2014, 10:24:10 AM »
Quote from: Bill Little on April 17, 2014, 10:22:17 AM
But, AFAIK, the .46LA will drop right in place of the .40LA..... ;D

BIG Bear
RNMM/AMM

I just did that a couple of days ago, as a matter of fact.
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Geoff Goodworth

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 808
Re: LA40 to LA46 conversion?
« Reply #4 on: April 17, 2014, 06:11:22 PM »
Gerald's right. The OD of the cylinder liner is greater on the LA 46 even though the stroke is the same on the FP 35/40 and the LA 40/46.
Logged

Offline Robert W

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 111
Re: LA40 to LA46 conversion?
« Reply #5 on: April 18, 2014, 07:43:31 AM »
I believe the heads are different.
Logged
AMA 28627

Offline richardhfcl

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 70
  • AMA 82448
Re: LA40 to LA46 conversion?
« Reply #6 on: April 18, 2014, 12:01:37 PM »
Gents,

     Perhaps we should say that the outside dimensions of the LA 40 and LA 46 are the same with the same footprint.  It is
easy to exchange one engine for the other in mounting in a plane.

     Is anyone really saying that the 46 and the 40 liners are interchangeable?  Just curious...
Logged
Richard Ferrell

AMA 82448

Offline FLOYD CARTER

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4462
    • owner
Re: LA40 to LA46 conversion?
« Reply #7 on: April 18, 2014, 02:00:32 PM »
The instruction sheet that comes with the LA 46 shows mounting dimensions for thr 40LA and 46LA the same.
Logged
90 years, but still going (mostly)
AMA #796  SAM #188  LSF #020

Offline Andrew Tinsley

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1345
Re: LA40 to LA46 conversion?
« Reply #8 on: April 18, 2014, 02:56:07 PM »
Hello Folks ,
Thanks for the info that the LA46 liner is bigger than that of the LA40 liner. Robert W the heads are certainly different as the bores are different! I might even bore out the LA40 crankcase to take the LA46 liner. It would be an interesting little mill exercise. Then I would have to shrink a band onto the head. Who wants to fly when you can play with engines!

Andrew.
Logged
BMFA Number 64862

Offline Tim Wescott

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12823
Re: LA40 to LA46 conversion?
« Reply #9 on: April 18, 2014, 03:53:04 PM »
Quote from: Andrew Tinsley on April 18, 2014, 02:56:07 PM
Hello Folks ,
Thanks for the info that the LA46 liner is bigger than that of the LA40 liner. Robert W the heads are certainly different as the bores are different! I might even bore out the LA40 crankcase to take the LA46 liner. It would be an interesting little mill exercise. Then I would have to shrink a band onto the head. Who wants to fly when you can play with engines!

Andrew.

Or just machine a new head.

When you have the case on the mill, scrape off the "40".
Logged
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Juan Valentin

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 587
  • USAF 1969-73 ANG 73-77
Re: LA40 to LA46 conversion?
« Reply #10 on: April 20, 2014, 08:50:06 PM »

     Hello Andrew
                                 You can remove the factory chamber and make a head button.
                                                                                                Juan
Logged

Offline RandySmith

  • Administrator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 13747
  • Welcome to the Stunt Hanger.
    • Aero Products
Re: LA40 to LA46 conversion?
« Reply #11 on: April 21, 2014, 10:02:58 AM »
If your having to buy " a new head , a new piston and sleeve, an new pin, a new crankcase, and a new gasket set.... why not just buy the motor for about the same price ..or lower, and keep you LA40 too

Randy
Logged

Offline Andrew Tinsley

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1345
Re: LA40 to LA46 conversion?
« Reply #12 on: April 22, 2014, 01:13:13 PM »
Hello Randy,
Somewhere in my shop, I have a new LA46 P/L, so it isn't quite as bad as you make out. I am enjoying myself doing some simple engineering and that is the main attraction. Doing it the "sensible" way as you suggest, I still have the LA40, which I simply don't rate as any where near as good a stunt engine as the 46. Some people enjoy flying F2b some like to play with engines and as flying is becoming more and more difficult for me, playing with engines is an alternative.
  I would rather practice some milling on a cheapie LA rather than ruin a decent engine.

Best Wishes,

Andrew.
Logged
BMFA Number 64862

Offline phil c

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2480
Re: LA40 to LA46 conversion?
« Reply #13 on: April 23, 2014, 06:51:19 PM »
The LA 40 can run just fine on the proper size plane with the right size prop.  I've had good luck in a 40 oz. Brodak Smoothie kit using  the stock muffler, a 10/4 prop and a .250-.260 venturi and an OS needle valve assembly.  Generally runs very steady on 10/11/11 fuel.
Logged
phil Cartier

Offline Steve Helmick

  • AMA Member and supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 9950
Re: LA40 to LA46 conversion?
« Reply #14 on: April 24, 2014, 12:04:02 AM »
The bolt pattern in the head/case is larger on the .46 than the .40, to make room for the bigger cylinder flange. Didn't look very easy to fix that, but maybe, with a bit of machining and welding...ewww. Might as well convert it to rear exhaust while you're at it. (Yes, it's been done to a .46LA)

Pete Ferguson had/has a .40LA that he got working nicely on a Profile Cardinal. The TT Cyclone 11x4.5 and 10-22 fuel were part of the setup. I think he started with the stock muffler and know he ended up with a Randy Aero CNC tube muffler, but that was just to get the CG right. The .40LA doesn't seem to like too much prop load at all. I would consider an extra head gasket, which might help that, as may more/different oil.  y1 Steve
Logged
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Andrew Tinsley

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1345
Re: LA40 to LA46 conversion?
« Reply #15 on: April 24, 2014, 07:27:42 AM »
Hello Phil and Steve,
I don't deny that you can get an LA40 to run well, I have seen one run well on one on one Mick Castell's planes. My point is that it isn't such a no brainer as the 46. You have to work fairly hard to louse up a 46, whereas you have to work fairly hard to get a good run from a 40. My best 40 setup was with a TT 11x4.5 and fuel having half and half castor at 20% with 5% nitro. Nowhere near as good as flying it with a 46.
  Just my experience and I am sure there will be many people that will be satisfied with the way their LA40 performs. I don't rate it much and I suppose others will, that is the way things go. If I want to make a mess of my 40 by doing a little machining exercise, then surely that is my choice!
  I remember one of my first posts on this forum. I actually like McCoy 35 redheads, their design is an excellent one for the period, let down by some poor material choices and even worse quality control. I wanted to rework a RH 35 using good materials and good machining practice. I was slagged off by some guy who said it was all a waste of time. Well I eventually went ahead and did it and a dreadful clapped out RH35 is now an excellent period engine!. My flying days are winding down due to ill health, so tinkering with engines is an alternative slant on the hobby. Thanks for the tip about hole spacing Steve, much appreciated.

Andrew
Logged
BMFA Number 64862

Advertise Here
Pages: [1]   Go Up
« previous next »
Tags:
 


Advertise Here