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L-21 Javron

You may need to add a seaplane lip to help with cooling so I would keep that in mind when it comes to the bottom cowling.
DENNY
 
You may need to add a seaplane lip to help with cooling so I would keep that in mind when it comes to the bottom cowling.
DENNY

He’s got some pretty good vents on the lower cowl (post 88). If you get the top side of your cowl sealed good, I’d bet you deal more with low temps than high ones.
 
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Next is the Oil cooler Not sure if I want it on the Baffling or mounted to the Firewall with a duct from the baffling
Any suggestions pro's and con's
What are those rubber hoses on the exhaust supports? Are they joining two pieces acting like a flexible connector? If so,good.

If you mount the oil cooler on the baffle be certain that you have substantial reinforcement to support and tie the weight of the cooler to a solid location on the engine such as the threaded holes on the cylinder head which are for the baffle screws. This support should also carry over to the crankcase. There is a 1/4" hole near the upper engine mount which is good for this.
 
What are those rubber hoses on the exhaust supports? Are they joining two pieces acting like a flexible connector? If so,good.

Exactly.
3/8 stainless tubing with 2.5" of hose. holds good and gives some dampening
im thinking the oil cooler will mount to the firewall with a support to the engine mount.
Still looking for ideas for this one.
 
Wouldn't solid support back to the engine be better? Those "dampers" will allow flex. With enough flex cycles something will crack and break. Wouldn't the exhaust and engine being tied together as one unit be preferred?
 
Kind of hard to tell from the pictures but the vents look to me to be more pockets for the exhaust. The actual open vent area looks small compared to a reg lower cowling.
DENNY
 
Wouldn't solid support back to the engine be better? Those "dampers" will allow flex. With enough flex cycles something will crack and break. Wouldn't the exhaust and engine being tied together as one unit be preferred?

It has ball joints forward of the mufflers to allow flex and prevent cracking. That is how RVs and is how I have been doing Maules to keep from cracking the exhaust from the long arm hanging out there. Actually works very well. I have used rubber muffler strapping from the firewall as well.
 
Interesting. I'll look at mine tonight. My muffler hangar is rock solid and are more in line to support the weight against gravity. Works perfectly.

The dampers mounted at approx 90* from each other will pretty much cancel out any flex but how effective are they at supporting the weight? As Mike would say.... pre-flight item. ;)
 
I went with this muffler support because this is what Vetterman sent with the exhaust. They do hold the mufflers solid.
I used aero quip hose and a clamptite tool to hold them in place. Don't think they will come off.
We will see and I'll keep an eye on them.
 
Wouldn't solid support back to the engine be better? Those "dampers" will allow flex. With enough flex cycles something will crack and break. Wouldn't the exhaust and engine being tied together as one unit be preferred?
If the supports in the above picture were solid, it would be necessary for the clamps where they attach to the tail pipe to be a loose slip fit. If not, the stresses when the pipes heat up and are shaken will break the end of the support tube or some other component where it is attached. There needs to be a place for motion even if it is only the clamp being able to slide on the tailpipe.
 
It makes no sense to me. I want my entire exhaust to be anchored to the engine so the entire engine-exhaust system moves at the same rate and time. If the tailpipes aren't in synch with the flanges at the engine something in between will flex, and that doesn't end well. As for the "ball joint" at the mufflers? Mine don't appear to give. I assumed the purpose was to allow some change in angle from collector to muffler, as opposed to having a welded flange. I have a hard time believing it's engineered to move, but what do I know? I found the muffler hangers interesting, and having just dealt with mine a few days ago the assembly is fresh in my mind.

I didn't mean to criticize the topic project. It looks great.
 
If the pipes are short they are connected to the engine via a flexible attachment and if the pipes are further aft the angles don't work for attaching to the engine so they go to the airframe like Maules do. The RV guys have it figured out. I am sure it is like everything where one way doesn't work for everyone but works for some.
 
Avnxtek, the cowl support rods that you have attached to the motor mount, where did you find the aluminum blocks mounted on the motor mount? They look much better than the piper clamp that most use. Good looking work, I also had to put a blister on my cowling to allow room for the Vetterman exhaust, my cowl is carbon fiber so a little easier to form. Thanks
 
The ball joints should give, sounds like you have the bolts to tight, there are suppose to be springs with the 3/16 bolts and there is a measurement that came with mine for how tight it should be. Never seen an exhaust that did not break with time if it can not flex
 
Guys in the Acro community have learned through experience (and high G’s) To hang directly to engine with no hangers. Course you also have finger straps added to flanges.Like Greg said, They all are very high maintenance. My RV-4 has hanger style. Has been trouble free for alota hours.
 
Avnxtek, the cowl support rods that you have attached to the motor mount, where did you find the aluminum blocks mounted on the motor mount? They look much better than the piper clamp that most use. Good looking work, I also had to put a blister on my cowling to allow room for the Vetterman exhaust, my cowl is carbon fiber so a little easier to form. Thanks


I couldn't find anything i liked so I had to make them myself. Experimental aircraft are so much fun
 
Kind of hard to tell from the pictures but the vents look to me to be more pockets for the exhaust. The actual open vent area looks small compared to a reg lower cowling.
DENNY

They were made to give clearance for the mufflers more than anything. they are small for a cowling vent I think they look better than a pocket for clearance and will help some. Once I get everything in place I'll probably work on a seaplane lip also
 
Just about have this Baffling done
I have the Baffling around the flywheel to go yet. I see some use it and some don't any opinions on that?
I'll wait on the seal until the final install

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Oil Cooler went to the Firewall I'm waiting on some flanges to come in to finish that up

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Been working on the Throttle levers for a long time now Finally got them done
the bracket holding the cable is just a temp

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Hope to get this Firewall forward done so I can start on the Wings

All Fun
 

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I have the Baffling around the flywheel to go yet. I see some use it and some don't any opinions on that?
Just fit your baffles tight enough to prevent as much airflow as possible to pass from the top to the underneath in this area, You want all of the cooling air to pass through the cylinder fins. Some make a streamlined shroud that fits behind the flywheel others just fit flat stock in tight. Same results. If you had a high speed airplane it may pay off to spend some time with streamlining the baffles.
 
Well I think I'm far enough along with the firewall forward to move on to the wings

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Oil cooler I used a 3" SCAT with a butterfly valve

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More baffling around the flywheel. Should seal up good. I hope!

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So so ready to start on the wings

Anyone have a good drawing for inspection hole placement ?
 

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...So so ready to start on the wings

Anyone have a good drawing for inspection hole placement ?
This is where you make your own. Study your wings for every place that you may need access or that there is something that may need looking at. Then place an inspection ring there making sure that you have room to get your hand in and around any obstruction that may be there. Don't depend on someone else's drawing.
Look here: http://www.supercubproject.com/drawings/ There may be a drawing that gives you what you are looking for.
 
I like to lay tape measure on wing before cover and take a picture of tape near each location that I may need to access for maintenance in the future.... make your life easy now, you might need in there again.. not that i cut them out.... just in case you need...
 
I covered the bottom of the wing first, then marked my inspection hole locations with a pencil from above. So far so good on the locations.
 
Some progress on the wings

I extended the top of the leading edge to the tip

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Made a removeable access panel at the flap

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Started with the top

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Finally got got to try out my wing rotator
I made it when I was waiting for the kit

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Inspection holes 8 of them

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Wing tip light

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Still working on rib stitching

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Off to the shop to tie some more knots
It's all fun
 

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