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MY AVID Mk4 RX-1...build

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Posted

I started this project, like most people who retire...with somewhat unrealistic goals. Those were soon squashed...and I had to  

resume, on the same pace as when I had a job. Now, my time is being pulled in so my directions, I am lucky to get anything done... but

I plug away...As far as posting  all this...I am not a very good typist  or computer wiz...so we will see.

I am doing everything...tube bending to welding...and trying to enjoy the work.

 

Here is where we start...Tore out the 582 ...FWF

 

Next...I set up a laser and determined how big to build a box...to put on top of the cart. You can see the studs and crossover

piece...sitting up front. I decided early on, that I wanted a one-piece motor mount...and that I was only using original connections.

Built the motor mount with the idea of using the original airbox as well....That may change. The crossovers may also serve as 

mounting points for oil/water tanks etc

 

Next...Mount with caps and crossovers in place...After that...just a lot of bracing tacking and fitting.

Here is a pic of the finished mount.. I decided to just paint it...so any cracks etc will show up easier upon inspection...I thought

the powder coat could hide things.

 

Here it is hanging...   Next, start exhaust.

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Posted

Nice!  I better kick it in gear here or you're gonna pass me up!

Looks like you'll have the same "bubble top" cowl as me, or are you going to be able to fit it under there?

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Posted

You are exactly right...I have to lengthen mine 6" anyway....So what is a little "Bump out" ..on top. 

I can't afford to pass you up...You post great ideas...and sources...That I will have to use anyways...:lmao:

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Posted

Here is a positioner, that I built off U-tube, using a bicycle...it is powered by a cordless drill...zip tied to

the frame. To the right ...is an adjustable rest. Worked great on the studs and the exhaust flanges

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Posted

The start of my exhaust system...I ordered a box of 36 feet of misc. bends a.k.a.  rejects from and

exhaust company. Summit Racing...is who I ordered from...1 3/8" exhaust bends

That and a collector (4 into 1) from Great Plains and I am ready to go.

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Posted

Placed the collector... and bent a heavy piece of electrical cable (I picked 28") to simulate my pipe.

Here is my first pipe... tacked up. You can see the cable hanging off the mount. 

I placed the collector so it is a straight shot to the exhaust can...which I will weld a mount for... off of

the nose gear brace.

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Posted

how come on these engines you guys run 4 pipes can you not just make a manifold type exhaust and go into one pipe?

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Posted (edited)

how come on these engines you guys run 4 pipes can you not just make a manifold type exhaust and go into one pipe?

These puppies need to breath right or you will miss out on a ton of HP that they are capable of.  Header design is well beyond my knowledge and experience so I went with advice from others, but here's a quote from a performance shop that sheds basic light on the topic:

"Header primary tube tuning has two basic parameters: airflow requirement and exhaust pulse tuning.

Tubing diameter is dictated by flow requirement, which in itself is determined by engine displacement and rpm...

Header primary length has to do with timing the exhaust pulses so that the exhaust from one primary helps to suck the gases from an adjacent cylinder."

 

It gets real deep.  Bore, stroke, valve duration, and other factors change design parameters.  But in a basic sense if the header isn't done right it will have the effect of putting a potato in your tailpipe!

Edited by Yamma-Fox
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Posted

Thanks...Y-Fox. I do NOT design anything...I merely shadow paths.. blazed by others. They have done all the REAL work. Testing...over and over...improving as they go

I show up...when everything is pretty well figured out....and build what works for me. Simple as that...          John O

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Posted

Me too!!  ^^

I never would have went Yamaha until others dialed it in and proved it out.

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Posted

Two pipes down...

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Posted

This is how the piping turned out. I had to re-do the last pipe. When it was done, the first time...I measured it, and found it to be an inch short. Cut it, and added "more swoop" on the bend...and worked out perfect.

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Posted

Here is the collector...adaptor piece marked for O2 sensor

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Posted

Wow!!

NICE.

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Posted

Turns out...that wasn't how the piping turned out. After building the last pipe twice already...I realized that the

profile was too wide, with the pipes stacked 3 wide as in pic 1...So I cut it off and...It is a little uglier, but the

length is good, and the profile...much slimmer.

Got the hole drilled and the bung for the O2 sensor...welded on, as well

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Posted

Very impressive! 

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Posted

Thanks Fred...Mostly a combination of "By Eye" construction....and don't forget...." I do it right..because I do it Thrice."   

                        You make some great films...by the way!

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Posted

Looking Great John!!  Glad to see you are making progress and at a steady pace at this point too!  I've been wanting to reach out to you to see how things were going.  Keep up the Great progress and you will be hitting the snow soon!  Cheers Randy 

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Posted

Good to hear from you, Randy. Hope you are getting lots of work time in (plane work that is). Been meaning to reach out as well...and Thanks again..

for getting that spline gear to me. Thanks to you...there is now a purdy little clutch unit.. sitting in that gearbox. One of my biggest problems now....is

I want to replace everything...Just ordered a piece of stainless...Yup...new firewall. Tore out half my panel...going to put in new windshield...AND...pretty sure I am

going to extend the pedals (mod)….I don't even have fuel to my non running engine..yet. Oh yeah...new fuel system too. See, it never ends.

Glad I'm not building a whole plane...   John O

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Posted

How heavy is that engine full up ready to fly?

John M

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Posted (edited)

They come in 165-180 with everthing less prop and radiator.

Below is Steve Henry's weight worksheet for his new Apex and it includes the radiator.

 

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Edited by Yamma-Fox

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Posted

Thanks Y-Fox... I am anxious to weigh mine, when all is said and done. Don't know if my figures will be anything anybody can use.

I make a better tank builder, than plane builder. This is all just practice anyway...

I already want that Apex... and a bigger plane, to put it in....  John O

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Posted

Can't believe it has been so long since I checked in.

I haven't done a lot of work...Have moved an hour from the hangar and had lots of other " life "  distractions.

Have added lots of work "to do"...New firewall...Stainless.  I am over 6' tall...so am extending the pedals "mod" as well.  New fuel system...  To name a few

Oh yeah...a whole new panel as well. Almost forgot since I have waited 3 months for instruments from MGL...

The stainless firewall work was harder than expected...No shears and no brake...makes for hard work. I have completed

the basket for the hole...It was my first shot at solid rivets...A learning experience :huh:     pics to follow on that.

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Posted

This is great! I'm doing a model c /RX-1 now. How is your progress going? I like the idea of doing the "extending the pedals mod". What are you doning for fitting the cowling? 

Thanks!

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Posted

Thanks Fred...Mostly a combination of "By Eye" construction....and don't forget...." I do it right..because I do it Thrice."   

                        You make some great films...by the way!

That's called the "TLAR" method! Used exclusively in homebuilding. In other words, " That looks about right".

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