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  #1  
Old 04-08-2021, 07:11 PM
Draker's Avatar
Draker Draker is offline
 
Join Date: Jun 2016
Location: Livermore, CA
Posts: 487
Default Show me your horizontal induction snorkel fit!

Are there any good build logs that depict the steps needed to get this snorkel done? Vans' plans, well, they leave a lot to the imagination. I have an E-mail chain going with the mothership, but I thought I'd request any pics VAF builders might have, too. When properly attached to the injector servo and rotated so the inlet faces up, I'm observing the following problems:

1. The snorkel inlet is not centered horizontally behind the cowl inlet--it is pretty far outboard. No amount of rotation seems to improve this.

2. The snorkel inlet is too far forward, you can see in the below picture it actually contacts the cowl inlet.

3. The snorkel inlet is too high. My guess is it needs to get cut before aligning with the metal inlet ramp.

4. Assuming I need to cut the top of the snorkel, I will need to both match the angle of the inlet ramp AND possibly the horizontal tilt of the cowl inlet. Will the air filter still fit in the resulting oblique shape?





Is this an acceptable position for this thing, or do I need to think about chopping it up?

I've read the various "Frankensnorkel" threads [1] [2] where builders have chopped theirs all apart and/or re-made them. Trying to avoid having to do this if possible. But if I gotta do it, I'll do it.

Anyone have good step-by-step pictures of this sub-assembly? It would help me figure out if I'm on track or not. The more stock, the better!

EDIT: Oh, and since it's probably important: IO-360-M1B
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Ryan Drake
Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 12/31/2020
RV-7A (N12VD): Empennage and wing kits complete minus fiberglass. Fuselage, wiring, and canopy complete. IO-360-M1B mounted. Cowl, baffles, induction mostly done.

Last edited by Draker : 04-08-2021 at 07:16 PM.
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  #2  
Old 04-08-2021, 07:13 PM
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jcarne jcarne is offline
 
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Location: Worland, Wyoming
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Default

Start at post 534 here. I had to go a bit off script unless I wanted to modified it around the starter. It is working just dandy right now! And yes, the filter will fit in the weird shape that you have to trim it to. It is rather flexible.
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  #3  
Old 04-08-2021, 10:51 PM
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wcalvert wcalvert is offline
 
Join Date: Jan 2019
Location: Anacortes Wa
Posts: 184
Angry My snorkel and I are not speaking right now

Let me say that the baffle / snorkel project was one of the most off script so far.

My build is a -7 with an AeroSport IO-360, Precision servo and Skytek NL-149 starter. The snorkel shipped by Vans was unlabeled before the troubles began, so no help with a part number there... ( I almost feel like the one I got was for a -14 ?) The only thing I can say about that part was that it cleared the starter just fine (after removing the two unused lugs on the starter).

The rest of the construction was a show... and not the good kind.

I'll admit that the only real way I could have wrapped my head around all this was to see a plane in person where measurements could be made.

In the end I cut the snorkel in two in order to shorten it about 1 1/2", and rotated it slightly for alignment. The filter mount ended up being nothing like the plans that came with the parts (actually, I did use the S shaped pieces to hold the filter) but the rest was my own design.

If I did this all again, I would mount the snorkel to the servo (temporarily) before doing any of the cowl fab on the left front corner. See how the intake end of the snorkel lays out and then build your cowl and filter box to fit the intake. I had to go back and rebuild part of the baffles there to get everything to line up. You might also consider doing something like is done on the -14 with a flange that mounts to the cowl and screws into the snorkel. Mine is one piece.

So, I will include a couple of photos. It did work, but not without a lot of creativity.

Good Luck!
Attached Images
    
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Start 2/19 Emp complete 4/19 Wings complete 11/19 Fuse complete 6/20 Finish kit Complete 8/20 Electric/Avionics complete 9/20 Engine hung 2/21 Moving soon for assembly 4/21 - truckin' on...
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Last edited by wcalvert : 04-12-2021 at 03:17 PM.
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  #4  
Old 04-09-2021, 04:14 AM
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rzbill rzbill is offline
 
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Location: Asheville, NC
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Default

I did not follow the instruction order on my -M1B snorkel install.

I decided where I wanted the filter to be, fabricated the filter cage and ramp area and then cut the snorkel apart, fitted both ends to injector and filter cage and glassed it back together.

My notes say the filter centerline was 3/16 outboard of the center screw in the angled baffle piece on the front of the cylinder. Filter is aft as possible. Flush with edge of baffle angle piece.

Like the instructions do say, this ramp needs to be twisted to match the engine baffle and cowl inlet lines. The filter fits fine. The twist is not noticeable after construction.

Afterwards, the snorkel inlet needed to move 3/8" aft and 3/4" towards craft centerline.

Study where to cut. Choose and do it.


***Edited*** I got home and had access to my log pictures that follow:
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Bill Pendergrass
ME/AE '82
RV-7A: Flying since April 15, 2012. 850 hrs
YIO-360-M1B, mags, CS, GRT EX and WS H1s & A/P, Navworx
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Last edited by rzbill : 04-09-2021 at 06:42 PM.
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  #5  
Old 04-09-2021, 05:20 AM
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rv8ch rv8ch is offline
 
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Default

Looks good - I'd say you are very close. Just need to trim as needed. If it touches something, cut it and put a patch on it. There are parts that you can't easily change, like the angle of the ramp and the size of the filter and the servo inlet - use these as constraints, and cut everything else. If you go to far on the snorkel, it's easy to re-do it since it's fiberglass. You can also trim the intake on the cowl - it does not need to be as deep as stock, since you will have some rubber/silicone baffle material.
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  #6  
Old 04-09-2021, 06:48 AM
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pilotkms pilotkms is offline
 
Join Date: Mar 2007
Location: WARNER ROBINS, GA
Posts: 470
Default Final Fit

When u get the snorkel figured out, 3 suggestions that have worked well for me, 600+hours.
1 - install nutplates to attach the air dams in front of the cylinders. May or may not need to change their size.
2 - put a 90deg bend into the front of that top plate to give it some strength, rigidity.
3 - I put the label on the alternate air door to advise me at annual that I didnít lose a washer and nut into the engine.

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RV 7A RV #9700 May 2017
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  #7  
Old 04-09-2021, 07:09 AM
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mburch mburch is offline
 
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Location: Oregon
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Default

Quote:
Originally Posted by Draker View Post
Are there any good build logs that depict the steps needed to get this snorkel done? Vans' plans, well, they leave a lot to the imagination.
I have the same airplane and engine as you. Here's a series of entries from my build log that show how I did mine:

http://www.rv7blog.com/2011/01/02/ba...r-duct-filter/
http://www.rv7blog.com/2011/01/16/air-filter-brackets/
http://www.rv7blog.com/2011/01/23/ai...etaining-ring/
http://www.rv7blog.com/2011/01/30/left-baffles/

I did have to alter the shape of my duct in one place to allow it to clear the alternator. I also had to figure out a lot of the filter mounting bracket stuff on my own - hope some of these pictures help. There's a lot of this kind of thing involved:



Quote:
Originally Posted by pilotkms View Post
1 - install nutplates to attach the air dams in front of the cylinders. May or may not need to change their size.
2 - put a 90deg bend into the front of that top plate to give it some strength, rigidity.
These are both good ideas - I did the same on my installation.
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Last edited by mburch : 04-09-2021 at 07:15 AM.
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  #8  
Old 04-09-2021, 07:21 AM
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bjdecker bjdecker is online now
 
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Default Alignment

Getting the right snorkel (VA-132-1,2,etc.) to fit the IO-360-M1B or IO-360-A1B6 with the Avstar/Precision/Bendix FI servo was a challenge.

I made a tool to facilitate this alignment, allows for a soft-fit so you can reliably reposition/rotate the VA-132-2 to the correct angle, etc.

2" SCH 40 PVC with a slight bevel cut into the end that mates to the FI servo. Hold in place with masking tape. Fit the VA-132 over and rotate into position.

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2020 RV-14 QB -- Under construction - Tailcone & Empennage Complete.
2018 RV-7 QB -- Built, Flying
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  #9  
Old 04-09-2021, 07:44 AM
rapid_ascent rapid_ascent is online now
 
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Location: Dublin, CA
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Default

Ryan, You didn't show any pics of the lower area. From looking at some of the other posts it seems there is normally an interference with the starter that needs to be cleared. If you haven't done that yet maybe that is resulting in the intake being rotated outboard. If you were to make those clearance cuts would that allow the intake to rotate inboard and essentially move the top inboard? At least from your pics that seems to be your biggest problem. The top will need to be trimmed at some point too I assume.
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2020 Donation Paid
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RV-7 Fuselage in progress
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RV-7 SB Wings
* Both Wings fully skinned
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* Ailerons Complete
* Flaps Complete
RV-7 Empennage - Complete (a little fiberglass work left)
Vans Training Kit # 2 - Complete
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  #10  
Old 04-09-2021, 09:51 AM
Draker's Avatar
Draker Draker is offline
 
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Location: Livermore, CA
Posts: 487
Default

Quote:
Originally Posted by jcarne View Post
Start at post 534 here. I had to go a bit off script unless I wanted to modified it around the starter. It is working just dandy right now! And yes, the filter will fit in the weird shape that you have to trim it to. It is rather flexible.
Thanks, Jereme, how did you decide the angle of the #2 side baffle? Was it arbitrary, or were you aiming for a certain amount of metal outboard of the filter hole? I see you put the screws and angle bracket on the outside. I may have to do that too.

Quote:
Originally Posted by wcalvert View Post
-
Quote:
Originally Posted by rzbill View Post
-
Seems a lot of people do end up cutting the snorkel in half and glassing it back together. I'm hoping to not do that, but I suppose it's not the end of the world.

Quote:
Originally Posted by pilotkms View Post
When u get the snorkel figured out, 3 suggestions that have worked well for me, 600+hours.
1 - install nutplates to attach the air dams in front of the cylinders. May or may not need to change their size.
2 - put a 90deg bend into the front of that top plate to give it some strength, rigidity.
3 - I put the label on the alternate air door to advise me at annual that I didnít lose a washer and nut into the engine.
Already did #1. #2 and #3 are great ideas. Thanks!

Quote:
Originally Posted by mburch View Post
Exactly what I was looking for! Nice step-by-step. Thank you very much!

Quote:
Originally Posted by bjdecker View Post
Getting the right snorkel (VA-132-1,2,etc.) to fit the IO-360-M1B or IO-360-A1B6 with the Avstar/Precision/Bendix FI servo was a challenge.
This is another great topic: How to ensure good alignment of the snorkel with the FI servo. I'm a little worried that my "wood cylinder" is moving around quite a bit as I rotate the snorkel, I can't seem to tape it on very securely. I was thinking about instead making a wooden cube "Fake servo" that bolts into the engine case and has the cylinder rigidly attached where the real servo inlet would be. No tape needed.

Quote:
Originally Posted by rapid_ascent View Post
Ryan, You didn't show any pics of the lower area. From looking at some of the other posts it seems there is normally an interference with the starter that needs to be cleared.
Hey, Ray. That's one thing I did not encounter that a lot of builders do: I'm seeing no clearance problem with the starter. There is something that stops the snorkel from rotating any farther counter clockwise, and I'm going to have to figure out what that is so the snorkel doesn't rub on it, but whatever the obstacle is, it's not the starter.
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Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 12/31/2020
RV-7A (N12VD): Empennage and wing kits complete minus fiberglass. Fuselage, wiring, and canopy complete. IO-360-M1B mounted. Cowl, baffles, induction mostly done.
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