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Author Topic: Johnson 35 stunt  (Read 2884 times)

Offline Bootlegger

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Johnson 35 stunt
« on: December 16, 2020, 08:11:25 PM »

 Guy's that are running/using these engines in stunt care to share the set ups that you are using, prop, fuel needle valve and any other info that you have..  I'm obliged... y1    #^    :!
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Offline RandySmith

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Re: Johnson 35 stunt
« Reply #1 on: December 16, 2020, 09:38:18 PM »
Guy's that are running/using these engines in stunt care to share the set ups that you are using, prop, fuel needle valve and any other info that you have..  I'm obliged... y1    #^    :!

Hi  as  I mentioned  in your  email to me, use at least 25% oil  mostly castor, 2 to 3 % needs to be  synthetic, The Needle  that comes with  it  is  good,  10 x 5 prop  for stunt.  or  if your doing  something  different  prop accordingly . Hot  long plug like a  SIG RC long  or  Glo Devil #300

Randy
« Last Edit: December 17, 2020, 10:27:49 AM by RandySmith »

Offline Bootlegger

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Re: Johnson 35 stunt
« Reply #2 on: December 17, 2020, 06:30:51 AM »

 Randy, I looked at the email and it said 25% castor, the post says 15% castor what gives?    H^^
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Online Brett Buck

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Re: Johnson 35 stunt
« Reply #3 on: December 17, 2020, 08:44:33 AM »
Randy, I looked at the email and it said 25% castor, the post says 15% castor what gives?    H^^

    Typo, use 25%+.

       I don't know much about these engines, Randy and others know more, but one thing I have heard from anyone who had one  - they take *immense amounts* of break-in, like 3-4-5 hours.

     Brett

Offline RandySmith

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Re: Johnson 35 stunt
« Reply #4 on: December 17, 2020, 10:28:38 AM »
Randy, I looked at the email and it said 25% castor, the post says 15% castor what gives?    H^^

typo  i fixed  it  should  say  25%

Randy

Offline Howard Rush

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Re: Johnson 35 stunt
« Reply #5 on: December 17, 2020, 12:36:31 PM »
Thanks.  Coulda hurt my Johnson.
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Offline Bootlegger

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Re: Johnson 35 stunt
« Reply #6 on: December 17, 2020, 12:40:30 PM »
 Thank you, now can anyone else recommend break in time and procedure, I see where Brett recommend several hours of run time, don't know if I will fly it or not at this time, sorta thinking about a Midwest Magician, but sure but am open to other suggestions, and Much Obliged again    D>K    H^^ 
  Again thanks...
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Offline Double Deuce

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Re: Johnson 35 stunt
« Reply #7 on: December 17, 2020, 02:28:15 PM »
As the story goes, the Johnson pistons were sintered iron and until a layer of crud and corruption from the break in running formed on the piston crown, they actually leaked thru the sintered particles, thus the need for an extended amount of running before being really ready to get it on. I never owned one so I am relying on memory(?)  of hear say from a long time gone by.

Certainly hope I have the correct engine to say this about. If I am wrong here, please be advised I am bumping my 86 trip around our Sun, and delete the info here in.

Double Deuce

Offline RandySmith

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Re: Johnson 35 stunt
« Reply #8 on: December 17, 2020, 02:38:54 PM »
Thank you, now can anyone else recommend break in time and procedure, I see where Brett recommend several hours of run time, don't know if I will fly it or not at this time, sorta thinking about a Midwest Magician, but sure but am open to other suggestions, and Much Obliged again    D>K    H^^ 
  Again thanks...

They normally take  a  lot of  time  to break in,  Run  2  to 3  ounces  at a  time, run it  very rich to start, then  after the  3rd tank,  same but  pinch the fuel line  very briefly  to let it  beep into a leaner  run for about 1 to 2 seconds,  You should  start  to be getting a feel  for  how  it is  coming in, do not  get it  too hot. They are  tougher  than a  35Fox  but  you can hurt them  by too much heat.
After  you get  30 minutes on it, turn the  needle  into a  full  rich  2 cycle for a  8 to 10 second  run,  do this  several times  in the  runs.  Please  run on a bench  on never  try to do  it in the  air

Randy

Offline Ken Culbertson

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Re: Johnson 35 stunt
« Reply #9 on: December 17, 2020, 03:14:47 PM »
I ran one in the late 60's.  All they say is true, especially not flying it till it is well broken in.  If they go lean for an extended period before broken in they can be ruined and in the air is not the place to have that happen.  Once broken in it was a really good engine.  More power that a Fox.

Ken
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Offline Dennis Toth

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Re: Johnson 35 stunt
« Reply #10 on: December 17, 2020, 04:52:26 PM »
Bootlegger.
Go to this web site it has write ups on the Johnsons and many other engines.

http://sceptreflight.com/Model%20Engine%20Tests/Index.html

Best,   DennisT

Offline EddyR

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Re: Johnson 35 stunt
« Reply #11 on: December 18, 2020, 07:02:12 AM »
 I had great very good results with the stock Johnson. In the early 1970’s I was given five Johnson motors. Three new in the box and two with run time on them.  There was a note in each box from factory saying no breaking needed. That was wrong as each needed at least 1/2 hr bench run in. I gave all but one away to friends as I only needed one for a old time plane. One of the motors was a all chrome .29 and I sent that motor to George Aldridge for his collection. I used the one I kept for 10 years winning the old time stunt event at the KOI 5 years in a row with that motor. My motors were the older style with the angled exhaust . Never had a stunt supreme. Ran castor only fuel in them. They ran harder than a Fox but not like a green head. They ran well with stub muffler.
  Many on here might remember my AAsr with the wheel pants that was Johnson powered.
I think Bill little has my Johnson motor.
EddyR
Locust NC 40 miles from the Huntersville field

Online Brett Buck

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Re: Johnson 35 stunt
« Reply #12 on: December 20, 2020, 11:37:04 AM »
From http://www.modelenginenews.org/cardfile/j36bb.html :

Right from first to last, Johnson engines featured a sintered iron piston. This process is akin to pressure diecasting except a powder substance is used and while heat is involved, it is less than the melting temperature of the alloy. The result is a light piston, free from stress, that requires only reaming for the wrist pin, machining the outer surface, then honing to the bore. Johnson used a domed top design with a low baffle that could not have been produced by machining.

The sintering process is frequently used to make bronze bearings as it produces a porous compound that can retain oil—good for bearings and piston walls, but not so great for the crown! This problem was resolved by impregnating the inside and outside of the dome with a plastic compound during manufacture. Once burned, this acted like case hardening to form a tough crust on both sides of the piston crown that provided good compression, while allowing the walls of the piston to retain the oil retention properties [2]. However, this crust required up to five hours of running to form, hence the long "break-in" period specified for Johnson engines. We'll come back to the sintered pistons later.

Offline Dan McEntee

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Re: Johnson 35 stunt
« Reply #13 on: December 20, 2020, 11:50:23 AM »
   Now THAT is interesting! I had never heard of that before. Any other brands use this exact process? I know Fox pistons are sintered iron. Maybe McCoy also but neither had the extra step of the material application in the crown?   Again, very interesting.  I have a few Johnson engines, some of them NIB, and I'll have to remember this part.
   Type at you later,
    Dan McEntee

    PS to add;
     OK, I just read the page that Brett posted the link to, and found that McCoy pistons are more or less the same, and in a photo, both displayed some accumulations under the dome on the inside of the piston. If this is correct, what was the weak point of McCoy engines that caused them to be worn out so fast, the cylinder liner material or lack of hardness ?
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Online Brett Buck

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Re: Johnson 35 stunt
« Reply #14 on: December 20, 2020, 12:01:00 PM »
   Now THAT is interesting! I had never heard of that before. Any other brands use this exact process? I know Fox pistons are sintered iron. Maybe McCoy also but neither had the extra step of the material application in the crown?   Again, very interesting.  I have a few Johnson engines, some of them NIB, and I'll have to remember this part.

  The linked article suggests that someone in the LA area was the contractor for both Johnson and McCoy pistons. You can't easily make the piston top any other way, at least not in 1955. 

    Brett

Offline Bootlegger

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Re: Johnson 35 stunt
« Reply #15 on: December 22, 2020, 06:06:24 AM »

 First of all I want to say Merry CHRISTmas to all of Stunt Hanger flyers, and the question is where can I get some gasket sets for the Johnson  S S 35 engine?  Thanks... D>K   #^   :! 
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Offline Steve Helmick

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Re: Johnson 35 stunt
« Reply #16 on: December 24, 2020, 11:38:38 AM »
Check with RSM about laser cut gaskets. I've also read about somebody on eBay selling laser cut gaskets, but I haven't bought any from either.

IF I had a Johnson engine, I'd make soft aluminum gaskets for head and case/cylinder, and postcard-type material for the backplate. I'm waiting anxiously for RJL's impending release of a new batch of Stunt Supremes.  LL~ LL~ LL~ LL~ Steve
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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 RandySmith

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Re: Johnson 35 stunt
« Reply #17 on: December 24, 2020, 06:23:49 PM »
Thanks.  Coulda hurt my Johnson.

Howard  we  think  your old enough  to  know  how to take care of your  Johnson !

Randy

Online Brett Buck

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Re: Johnson 35 stunt
« Reply #18 on: December 24, 2020, 06:27:34 PM »
Howard  we  think  your old enough  to  know  how to take care of your  Johnson !

Randy

   There's the limit - 17 posts before we got to the obvious! Excellent, gentlemen.

    Brett

Offline Howard Rush

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Re: Johnson 35 stunt
« Reply #19 on: December 24, 2020, 11:03:54 PM »
Howard  we  think  your old enough  to  know  how to take care of your  Johnson !

Old?  It’s just getting broken in.
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Offline Dennis Saydak

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Re: Johnson 35 stunt
« Reply #20 on: December 25, 2020, 01:04:25 PM »
Old?  It’s just getting broken in.

Didja use the recommended vasaline?  ;D
Just when you think you're getting ahead in the rat race.....you find the rats just get faster! MAAC 13120L

Offline Bootlegger

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Re: Johnson 35 stunt
« Reply #21 on: December 25, 2020, 04:40:54 PM »

  Guy's I am asking where can I get a set or two of the gaskets for the Johnson S S 35...

  Can anybody help???
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Offline Dan McEntee

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Re: Johnson 35 stunt
« Reply #22 on: December 25, 2020, 04:56:16 PM »
  Guy's I am asking where can I get a set or two of the gaskets for the Johnson S S 35...

  Can anybody help???

    And several people have answered, both to this thread and your classified add.
    MERRY CHRISTMAS!!
   Dan McEntee
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Offline Steve Helmick

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Re: Johnson 35 stunt
« Reply #23 on: December 26, 2020, 02:12:49 PM »
Howard  we  think  your old enough  to  know  how to take care of your  Johnson !

Randy

Soak it in cider?  That's what one of my leadmen always suggested.  y1 Steve
"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 Bootlegger

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Re: Johnson 35 stunt
« Reply #24 on: December 27, 2020, 04:21:20 PM »

 Dan Thanks for the reply, I had forgotten about the other post..      H^^   y1
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Offline Steve Helmick

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Re: Johnson 35 stunt
« Reply #25 on: December 28, 2020, 03:27:54 PM »
There's a Howard's Johnson motel across from the NW Skyraider's usual meeting place.  :X Steve
"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.


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