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  #11  
Old 10-01-2020, 07:25 PM
rocketbob's Avatar
rocketbob rocketbob is offline
 
Join Date: Jun 2006
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Default

Flow straightener I made for a Rotec TBI. Works perfectly.
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  #12  
Old 10-01-2020, 08:11 PM
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scrollF4 scrollF4 is offline
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Default Frankensnorkel 2.0

Quote:
Originally Posted by rv8ch View Post
I'm kind of embarrassed to show this, but this is my snorkel.

It's hard to tell, but it's not as smooth as the Van's snorkel. I feel I have a lot of room to make it better. At least there is no place in there that has a smaller cross section as the FM-200 intake. But it is far from smooth with laminar flow.
Copycat.

https://vansairforce.net/community/s...frankensnorkel

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  #13  
Old 10-01-2020, 10:52 PM
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rv8ch rv8ch is offline
 
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Default Correct

Quote:
Originally Posted by scrollF4 View Post
Exactly where I "borrowed" the idea. That was an inspirational thread, but I should have listened to Dan and just put in a straight pipe.

Perhaps in round two.

I'd like to find a way to get a straightener in there without massive amounts of work - that will be a rainy wintertime project.

I also had the idea of designing something in CAD and 3D printing something better, but not sure my skills are up to that challenge.
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  #14  
Old 10-01-2020, 11:00 PM
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Daida Daida is offline
 
Join Date: May 2005
Location: Hannover, Germany
Posts: 175
Default don´t worry!!

don´t worry about the looks....it will disappear underneath the cowling anyway!

The cirrus pilot won´t notice when you overtake him/her!!

The look is just for you!!



Nice Valve covers though……..
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  #15  
Old 10-01-2020, 11:07 PM
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rv8ch rv8ch is offline
 
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Default intake shape

Quote:
Originally Posted by rvbuilder2002 View Post
The actual shape might be more of a concern than the interior surface finish. While developing the new snorkel for the RV 14 we discovered that the shape of the turn into the airflow performance servo is very sensitive. The explanation that Dan gave a few posts back about the differences in how the RSA versus airflow performance servos meter inlet air is I think a likely explanation. Because of this, before going to far, you may want to send your home made one to Don and ask him to flow test it for you
Thanks for sharing this Scott. Don mentioned this to me when I called him. I guess I have a few options:
  1. find a way to install a straightener
  2. remove the snorkel and change to a straight intake
  3. live with it (it's really not that bad)
  4. change the servo to something less sensitive to turbulent airflow at the intake

As much as I like building, I'm really going to struggle to take the aircraft out of service for any length of time - flying it is really enjoyable, and I'm only in phase 1 - I can only imagine how great it is to travel in it.
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  #16  
Old 10-01-2020, 11:49 PM
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What about guide vanes in the last elbow

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  #17  
Old 10-01-2020, 11:52 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by rv8ch View Post
Thanks for sharing this Scott. Don mentioned this to me when I called him. I guess I have a few options:
  1. find a way to install a straightener
  2. remove the snorkel and change to a straight intake
  3. live with it (it's really not that bad)
  4. change the servo to something less sensitive to turbulent airflow at the intake

As much as I like building, I'm really going to struggle to take the aircraft out of service for any length of time - flying it is really enjoyable, and I'm only in phase 1 - I can only imagine how great it is to travel in it.
The reason I mentioned it is that during our "experimenting" phase, we test flew a design that at certain power conditions, the engine would actually die for a couple seconds, come back for a couple seconds, die for another couple seconds,...... repeat, for as long as you left it in that condition. Caused a few instances of increased blood pressure, until we finally discovered what was causing it.

For those that make their own home made snorkel, having Don test it to tell you whether it seems to flow at a steady state through the entire throttle range could be worth while. If you are already flying yours and not having any problems then it probably isn't necessary.
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Last edited by rvbuilder2002 : 10-01-2020 at 11:57 PM.
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  #18  
Old 10-02-2020, 01:58 AM
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rv8ch rv8ch is offline
 
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Default stop/start

Quote:
Originally Posted by rvbuilder2002 View Post
The reason I mentioned it is that during our "experimenting" phase, we test flew a design that at certain power conditions, the engine would actually die for a couple seconds, come back for a couple seconds, die for another couple seconds,...... repeat, for as long as you left it in that condition. Caused a few instances of increased blood pressure, until we finally discovered what was causing it.

For those that make their own home made snorkel, having Don test it to tell you whether it seems to flow at a steady state through the entire throttle range could be worth while. If you are already flying yours and not having any problems then it probably isn't necessary.
Very interesting. I reduced the main jet size by a half size, and it has been much smoother since - perhaps that's a similar thing - spikes of either no flow or too much. Don was not too excited about doing this, but thought it would be worth a try. I have another jet one more half size smaller which I might try.

I described my snorkel and Don said it's probably extremely turbulent, and I'm sure he's right. I had no idea that it would even be an issue when creating it, but it's clear why now.

I might just cut a hole in the cowl try one of these.

https://airflowperformance.com/index...-duct-2-valve/

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  #19  
Old 10-02-2020, 05:13 AM
judoka5051 judoka5051 is offline
 
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Default Velocity Stack??

I've been following this closely since I'm molesting my snorkel too. I cut a hole in the front of my snorkel and added a ram air inlet. I'm currently working on the shutoff valve. I've been thinking about adding a short velocity stack to the servo inlet. Internet snooping shows different lengths, and of course they all add 'lots of horsepower'. I hate to disregard their results, but have you seen some of the aerodynamic doodads? Holy cow! Bolting a bathtub on there would be an improvement to some of the stuff I've seen.

Anyway, I'm curious to know if anyone else has tried the stack, and what the results were.

Regards, Lance
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  #20  
Old 10-02-2020, 05:18 AM
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Capflyer Capflyer is offline
 
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Add a scoop and the MK3 filtered ram air kit with the backplate that mates up to the FM200's optional connection sleeve.



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