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-   -   The Terrifying Tale of FrankenSnorkel ! (https://vansairforce.net/community/showthread.php?t=118549)

scrollF4 10-13-2014 08:21 PM

The Terrifying Tale of FrankenSnorkel !
 
<<WARNING: NOT FOR THE FAINT OF HEART OR STOMACH>>

Just in time for Halloween, let me tell you the chilling tale of a poor tortured FAB snorkel, one like so many others, that began its life as one whole and complete fiberglass item with dreams of living in a mighty fire-breathing 200hp IO-360. However, as (mis)fortune would have it, this snorkel ended up in a 180hp IO-360 firewall forward kit.

Again, like so many others, its kitbuilder saw need to dismember the snorkel horribly into two separate end pieces:



The snorkel's dismembered limbs were drawn to separate locals, then bolted under high tension to horrible machines of torture with names like fuel injection servo and intake ramp. Oh, the horror:



Then, the kitbuilder mutilated the poor snorkel to cram its mangled body into the most agonizingly tight spaces:



Oh, the horror...



Hideous metallic probes and studs were riveted to the snorkel's neck, like electrodes on a Hollywood monster:



When the mad kitbuilder was satisfied with his sadistic placement of the snorkel's two limbs, he hideously grafted them to the center part he had surgically removed before, transforming the once-beautiful fiberglass snorkel into.....FRANKENSNORKEL!!! :eek:




The mad kitbuilder wrapped poor Frankensnorkel in layer upon layer of rotting, festering, skin, making the monster even more monstrous:



....to be continued in episode 2....

scrollF4 10-13-2014 08:21 PM

Episode 2
 
He then clothed Frankensnorkel in the brightest ghost-white clothing, hiding the horror that lies just beneath the rotting skin:



And now, doomed to a life of torture under the cowl of an otherwise beautiful RV-7A, one can find the desperate gasps of the pitiful...
the wretched...


(wait for it)


FRANKENSNORKEL!! :eek:


Neal@F14 10-13-2014 08:52 PM

At least a portion of the tale is somewhat riveting.

longranger 10-13-2014 10:52 PM

I'm just hoping that someone comes out with one that "just fits" before I get to that point...

RKellogg 10-14-2014 04:10 AM

Cowl clearance??
 
Scroll, are you sure that your snorkel will clear the cowl? I thought mine was done when I was at that stage, but wound up visiting the bandsaw and belt sander again for further 'slim and trim'. After a while I started saving "spare" pieces...



- Roger

scrollF4 10-14-2014 04:47 AM

So far, so good.

Danny King 10-14-2014 07:16 AM

FrankenSnorkel
 
That sure is a terrifying tale. But I'm spooked as to why all that was necessary.
I've done four snorkels. One for the Doll, and three for other builders, and non of that was necessary! Are you sure you started with the correct snorkel? I wouldn't bet my life on it, but I believe there are two models.

I start by fitting the left baffling to the engine. Then I remove the front baffle piece that the snorkel fit to. Then I clamp the snorkel's flange to the throttle body, and swing the snorkel up until it just about hits the starter. Using the angles that attach the front baffle to the engine, I trace a cutting line on each side of the snorkel at the proper height and slope so as to match the front baffle. When I cut the snorkel, I add enough length to the cut to allow for the K&N filter to fit. Then I install the front baffle and cleco the snorkel to it using the mounting angles. Now you can see exactly where to cut the square hole in the front baffle, but I don't do that until the next step is complete.

(Note: I rivet a .040 doubler to the front baffle, and use the rubber seal of the K&N filter to make the seal with the baffle instead of using the filter mounting hardware. If you plan to use the mounting hardware the snorkel is not cut shorter to allow for the filter)

I cut off the snorkel's mounting flange at the throttle body. That angle is never quite right! With the mounting flange drilled and bolted to the throttle body, I glass the snorkel back to the flange at the correct angle.

The only cutting done to the snorkel is at the mounting flange, and to the other end to match it to the front baffle. There is nothing that horrifying about it!

As to cowling clearance.....it is very tight. It is important that the gap between the spinner back plate and front of the cowling be kept to a minimum!

The Doll has to places where the inside of the lower cowling contacts the snorkel during high G flight. I used a couple pieces of the nylon material Van supplies for the flaps to wear against the wing to insulate the contact points with the cowling.

rzbill 10-14-2014 09:24 AM

Danny,
Your sig file says angle valve motor. The OPs is a parallel. They are different widths.

While I imagine one can install the snorkel on a parallel valve without cutting it, its my opinion that the filter sits to far outboard and it affects the outboard baffle position negatively where it interfaces with the cowl.

RKellogg 10-14-2014 10:01 AM

FAB rework
 
I think my extreme snorkel rework was due to the cold induction manifold & adapter pushing the fuel servo farther forward... Many possible combinations.
- Roger

Paul K 10-14-2014 10:35 AM

Scroll, I feel your pain!

I used an IO360 with ECI cold air induction and the fit wasn't even close! I,m talking off by more than 1 inch on the inside and 3 inches on the outside plus it made contact with the starter flange and the alternator. I started out doing what you did to make it fit but was so totally turned off by the results that I tossed it in the junk and built one from scratch. Not that hard to do and ended up looking better than I dreamed it could! Give it some thought and feel free to call me with questions. It can be done!






JonJay 10-14-2014 10:51 AM

Very funny and well written tale of horror. I was involved with one of the very first applications in an RV8 around 1998 or so. Doesn't look like anything has changed. It was indeed horrifying.....

ppilotmike 10-14-2014 12:23 PM

Stupid question?
 
I'll be the guy... What mod requires this to be done.. Aftermarket cowl? I thought the FAB intake was essentially right out in front. :confused:

boom3 10-14-2014 12:39 PM

Quote:

Originally Posted by ppilotmike (Post 925035)
I'll be the guy... What mod requires this to be done.. Aftermarket cowl? I thought the FAB intake was essentially right out in front. :confused:

Both cowls are available from Vans. One has the FAB air inlet directly out the front and the other uses square air filter just inside the left cowl opening.(This is the one where you need a snorkel.) The difference is vertical vs horizontal induction.

RV9A Bill 10-14-2014 12:49 PM

Frankensnorkle
 
Mine took lots of fitting on an IO- 360 parallel valve.

scrollF4 10-14-2014 12:52 PM

This is the stock RV-7 cowl for an IO-360M1B 180hp horizontal induction setup, and the FAB came with the firewall forward kit. The engine is a factory-new stock Lycoming YIO-360M1B, and the baffle kit is also the stock Vans kit for the same engine. With the snorkel centered on the fuel injector, the FAB extended an inch past the left intake ramp and side wall. Vans confirmed that this snorkel will be too long since it's intended for the 200hp version.

Danny, thanks. I did a lot of what you described, but I'm gonna need more practice.

Paul, that looks great! I may give you a call later.

rightrudder 10-14-2014 03:36 PM

Highly impressive ductwork-ery. It might've been easier to vacuum-bag the fiberglass around the starter! :)

Danny King 10-14-2014 08:15 PM

Quote:

Originally Posted by rzbill (Post 924973)
Danny,
Your sig file says angle valve motor. The OPs is a parallel. They are different widths.

While I imagine one can install the snorkel on a parallel valve without cutting it, its my opinion that the filter sits to far outboard and it affects the outboard baffle position negatively where it interfaces with the cowl.

Yes, I realize that the parallel valve engine has less room to work with, but one of the engines I did was a Superior I0360 parallel valve with the new metal cold air sump. The snorkel fit the same way with a little more "centering" work at the flange. I figured at the time that the difference in the fit was because of the non Lycoming sump with placement of the throttle body close, but not exactly the same as the Lycoming.

I think Van sell two different snorkels. One for the parallel valve cylinders, and a longer one for the angle valve engines. I could be wrong, but I seem to recall that one snorkel part number was: ???? and the other snorkel was the same number with a -1 after it! (????-1)
YMMV

David-aviator 10-15-2014 05:31 AM

Quote:

Originally Posted by Danny King (Post 925181)
Yes, I realize that the parallel valve engine has less room to work with, but one of the engines I did was a Superior I0360 parallel valve with the new metal cold air sump. The snorkel fit the same way with a little more "centering" work at the flange. I figured at the time that the difference in the fit was because of the non Lycoming sump with placement of the throttle body close, but not exactly the same as the Lycoming.

I think Van sell two different snorkels. One for the parallel valve cylinders, and a longer one for the angle valve engines. I could be wrong, but I seem to recall that one snorkel part number was: ???? and the other snorkel was the same number with a -1 after it! (????-1)
YMMV

Danny,
The catalog shows one induction kit (-1) for the IO-360M1B and 1B6 engines going into the -7 or -8. The dimensions must be the same.

With the -7 I trial fit a snorkel to the cold sump with AFP FM200 controller and it would have required major changes to it and or the cowl, did not use it. With the 8, same set up except FM150 controller, the snorkel fit perfect, made one small mod to clear a bolt on the starter.

Things get complicated if the fuel controller is different than what comes with Vans engines. The FM150 is the same.

Paul K 10-15-2014 09:46 AM

Scroll,

I created a new picasa page of all the photos I took building the custom snorkel. Made lots of mistakes and would do it differently if I did it over again but here they are:

https://picasaweb.google.com/1033987...eat=directlink

BenNabors 10-15-2014 02:14 PM

Paul K: Any concerns for galvanic corrosion between the aluminum rivets and the carbon? The potential voltage is about 1.5 volts.

Paul K 10-15-2014 03:20 PM

Possibly, I set the rivets in wet epoxy and they get a good looking over at every oil change. I check the filter just because it is so easy to remove and that let's me see the rivets. I also check any contact points and so far, nothing.

For the future, fiberglass is also available in sock form and you really don't even need to use a sock. I was not going to paint it originally, liking the looks of carbon, but in retrospect would not use carbon again. It's hard to work with.

scrollF4 10-15-2014 06:11 PM

Quote:

Originally Posted by Paul K (Post 925313)
Scroll,

I created a new picasa page of all the photos I took building the custom snorkel. Made lots of mistakes and would do it differently if I did it over again but here they are:

https://picasaweb.google.com/1033987...eat=directlink

Paul,
I really do appreciate the album. As usual, photos help it all make sense. You would have justified leaving it unpainted.

jarhead 10-15-2014 08:17 PM

Quote:

Originally Posted by scrollF4 (Post 924848)


You might be surprised at the ductwork in certified helicopters (not just light singles, either) that looks pretty much like your pics above... at 0.0 TSN... from the OEM.

Bugsy 10-15-2014 08:41 PM

Scroll
Is this some Holloween tale, just drill a hole in the front of the cowl like everyone else and skip all this nonsense.

David-aviator 10-16-2014 05:11 AM

Quote:

Originally Posted by Bugsy (Post 925487)
Scroll
Is this some Holloween tale, just drill a hole in the front of the cowl like everyone else and skip all this nonsense.

That's what I did with the 7 and FM200. The engine liked ram air, I could feel difference after take off when it was opened. But then I had a rinky-dink internal filter that could have been improved.

scrollF4 10-16-2014 07:33 AM

Quote:

Originally Posted by Bugsy (Post 925487)
Scroll
Is this some Holloween tale, just drill a hole in the front of the cowl like everyone else and skip all this nonsense.

Ok, educate me please: Is there a horizontal snorkel option for the horizontal induction IO-360? I agree that it would have been easier to build...

...but my other hangup involves that guppy-mouth intake hole under the prop spinner. I just don't like the look, but I really do love the clean cowling look without the center intake. That's one of several reasons why I chose the IO-360.

SHIPCHIEF 10-16-2014 08:11 AM

Your Frankensnorkle made up my mind, I did what Bugsy said.
I just drilled a big hole under the spinner yesterday.
I have a parallel valve IO-360 with Superior cold air sump and Airflow FM-150 injector.
I'm using a nifty tubular aluminum housing with a K&N cone filter inside. That's attached to the injector by a 3" X 4" adapter hose. I'm planning to mold a fiberglass fairing around it...

Smilin' Jack 10-16-2014 06:40 PM

Guess I was lucky, with my snorkel missed all the vital components. A lot of
moving and repositioning to make it fit. But with the Precision Throttle body it cleared everything.

Smilin Jack

grubbat 10-16-2014 07:13 PM

Why not straight in?
 
Why don't you make a large NACA opening like the Mooney and go straight in to the servo?

SHIPCHIEF 10-17-2014 12:12 AM

Grubbat,
To answer your question about an NACA duct, on my RV-8: I Trial fit a 7" long piece of 3" hose from the injector body inlet. The end of the inlet hose is mostly outside the slope of the cowl.
If you used an NACA duct, there would be very little to no room for an air filter.
I'm trying pieces from a Spectre universal remote air filter, here is a link:
http://www.summitracing.com/parts/spe-9833/overview/
It has a cone shaped K&N filter inside. I'm ditching the short end and using a 4"x3" reducer hose to connect the wide end to a Flyboy Accessories fuel injector inlet adapter.
http://www.flyboyaccessories.com/Hom...sories-s/3.htm
The smaller inlet end sticks out into the airstream, a few inches behind the propeller.

scrollF4 10-17-2014 08:12 AM

Quote:

Originally Posted by grubbat (Post 925760)
Why don't you make a large NACA opening like the Mooney and go straight in to the servo?

Because I really like the appearance of the RV-7a nose with no intakes under the spinner. I'm sticking with the snorkel-to-left intake approach. The jury's still out on whether I'll replace FrankenSnorkel. :eek:

DanH 10-17-2014 08:27 AM

Quote:

Originally Posted by SHIPCHIEF (Post 925812)
I'm trying pieces from a Spectre universal remote air filter.....
It has a cone shaped K&N filter inside.

Scott,
No point in re-inventing the wheel. Sounds like a 4" dia base x 5" long cone filter. If so, it doesn't provide nearly enough media area to avoid a significant pressure drop. Don Rivera was kind enough to measure a similar filter for me, a K&N RU3120 with the outlet spigot removed. The test assumed 1400 PPH for the 390. Your demand would be a little less, but probably not enough less for a good result. Restriction gets worse when dirty.

The canister was 6" diameter, but otherwise is about what you're trying. Sorry.






PIN 37 10-18-2014 03:14 AM

Has anybody put a snorkel on an Airflow performance throttle body and if so, how did you do it ?

wjb 03-10-2019 07:21 PM

Quote:

Originally Posted by scrollF4 (Post 925041)
This is the stock RV-7 cowl for an IO-360M1B 180hp horizontal induction setup, and the FAB came with the firewall forward kit. The engine is a factory-new stock Lycoming YIO-360M1B, and the baffle kit is also the stock Vans kit for the same engine. With the snorkel centered on the fuel injector, the FAB extended an inch past the left intake ramp and side wall. Vans confirmed that this snorkel will be too long since it's intended for the 200hp version.

Yes! Exactly what I have and is exactly what I'm seeing ... I was puzzled by everyone who had the snorkel "just fit"; you can't really mess this up given the non-negotiable locations of the servo intake and left ramp.

I'm feeling "son of FrankenSnorkel" coming soon.

How did you support the center section when you glassed it? foam inside? Did n't look like it..

humptybump 03-11-2019 02:55 AM

If foam sculpting isn?t your forte and you have CAD skills and a 3D printer (or access to them) it?s possible to 3D print the ?plugs? with PLA. After fiberglassing, you warm the the part in the oven to 150F for an hour and it becomes soft enough to pull out.

Details here: http://elder.ninja/blog/p/7512

scrollF4 03-11-2019 03:34 AM

Quote:

Originally Posted by wjb (Post 1330701)
Yes! Exactly what I have and is exactly what I'm seeing ... I was puzzled by everyone who had the snorkel "just fit"; you can't really mess this up given the non-negotiable locations of the servo intake and left ramp.

I'm feeling "son of FrankenSnorkel" coming soon.

How did you support the center section when you glassed it? foam inside? Did n't look like it..

WJB,
I screwed each end of the snorkel to their positions on the fuel injection servo and the baffle, then laid two pieces of wetted cloth in place to bridge the gap. This essentially tacked it all into a single piece. The gap between the pieces was small enough that the cloth didn?t sag. Once cured, I removed the snorkel and laid up the rest of the fiberglass.

goatflieg 03-11-2019 03:11 PM

Interesting and timely thread for me; I'll be attacking the snorkel soon. Danny King, I've cut and pasted the instructions you laid out here. Paul K, I've downloaded your photos for future reference. Absolutely love the way it looks on the airplane. Since you're also in Michigan, if there's any chance I could see your aircraft in person, I'd be most grateful for the opportunity. I'll buy lunch. Lunch and dinner. In fact, I'll pay your grocery bill for a week... maybe.

scottmillhouse 03-12-2019 07:06 PM

After all the tales of whoa, surprisingly mine fit with lots of trials and small cuts at baffle side. No butchering and glass work. Appears it is designed to fit a real Lycoming and not a clone. Getting the filter in was challenging due to tight space. I had to take a lot off of the cowl and made a filter cover cap that tied in the snorkel side, side baffle and cover. RV-7A, Vans standard Lycoming IO-360 180 hp.

pilotkms 03-12-2019 07:18 PM

Not sure about your X across the face of the filter. Is there a purpose for it? U may be cutting off 10-20% of the airflow. And u want all u can get. Previous threads about screen material in front of oil coolers indicated significant reduction of airflow. Maybe the engineers will chime in.

wjb 03-12-2019 10:26 PM

Quote:

Originally Posted by scottmillhouse (Post 1331154)
After all the tales of whoa, surprisingly mine fit

Clearly, you must be living well and using the correct primer!


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