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  #11  
Old 10-07-2017, 06:29 PM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
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I am taking notes and pics as I go through this again.

When I finish up and everything goes good I will post the updated process and pics.
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Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47
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  #12  
Old 10-18-2017, 08:33 PM
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jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
Default Finished modifying new snorkel

I finally finished modifying the new snorkel.

As mentioned in the earlier post, the most important step in starting to modify the snorkel for the FM-200 throttle body is first mounting the snorkel to a Bendix style throttle body and taking note of the clearances to the starter, a few pics, and diagrams.

The next steps depend mostly on your artistic/technical savy and fiberglas modelling skills. In all the modifying, adjusting, trimming, mounting, and redoing all steps over again over a period of about a week finally resulted in finishing up. The modifying/adjusting/reglassing the snorkel had to be done in lots of small steps. I tried a bit of modelling with blue foam (Styrofoam) and also with soft filler material covered with spackling paste - these did not work that good for me. The thing that worked best for me was to build up the reglassing first with 0.90" stainless rods and narrow strips of fiberglass trimmings, and then laying patches of fiberglas cloth over the ribbing in 'patches' of area. The 'patching' allowed me to get to the interior surfaces of the patches to smooth and form. It also let me position the snorkel so that the wetted glas patches hung to form the patches in gentle curves (gravity assist) between the ribbing. If you are much more experienced with forming glas using foam molds that may be the way to go to do the glas work in fewer steps.

The resource available for me was being 16 miles from Airflow Performance at KSPA. I was able to take the snorkel and throttle body to Don Rivera and mount it on their air flow test equipment and measure all the operational specs. Everything was well within specs according to Don and his 30 minutes of explaining it all. I understood some of it, but parts of the explanation went a bit over my head.

The things that Don advised as I got more into the modifying was to avoid any air dams in the snorkel, especially at the >90 degree turn into the throttle body, and keeping the tunnel as smooth as possible.

My own vision of how the air was flowing at the bottom knuckel at the last turn seems to suggest that the air needs the extra bit of space to get around that greater than 90 degree turn. So I let the 'bulb' space be as large as I could let it be using the original snorkel form; you have to keep refitting it to the plane to make sure that everything stays compact an within the cowing space. That tight corner bend on the small radius needs a ramp and smooth bend around it into the throttle body.

In the next few days I will post a few of the pics that I took at the earlier stages.

Don Rivera says that there are more than a few aircraft out there using the FM-200 on 360 and 390 size engines and likely enough RV's that have modified the snorkel to fit. His installation manual has a few photos of RV snorkels using the FM-200. In my experience with it, it was accomplished and it does work properly and fits in the cowling and around the engine parts - took some time and a bit of effort.
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Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47

Last edited by jeffw@sc47 : 10-19-2017 at 06:27 AM.
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  #13  
Old 10-19-2017, 06:41 AM
Mark Dickens's Avatar
Mark Dickens Mark Dickens is offline
 
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Location: Collierville, TN (KFYE)
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Quote:
Originally Posted by jeffw@sc47 View Post
Don Rivera says that there are more than a few aircraft out there using the FM-200 on 360 and 390 size engines and likely enough RV's that have modified the snorkel to fit. His installation manual has a few photos of RV snorkels using the FM-200. In my experience with it, it was accomplished and it does work properly and fits in the cowling and around the engine parts - took some time and a bit of effort.
I'm one of these people Don is talking about. I installed a FM200A on my Titan IOX-370. With only 1/2" clearance between the bottom lip of the injector intake and the cowl, the snorkel wasn't going to fit. I had two choice, put a blister in the cowl or put a forward facing scoop on the cowl and route the intake air directly into the injector. I ended up doing the latter and am happy with it, although it took a lot of time. I had to route all of the control cables in a custom way and fabricate my own brackets. A real PITA although I am happy with the end result.
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RV-8 #81077 Super Slow Build
Titan IOX-370, Dual P-Mags, AFP FM200A FI, Sensenich GA Prop
First Flight November 20, 2016
Phase One Complete June 1, 2017
http://www.marksrv8.com
2017 Donation Complete!
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  #14  
Old 10-22-2017, 09:08 AM
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jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
Default Snorkel mod to FM-200 progress pics with notes

Here are some pics from starting the snorkel modifications through to lots (and lots) of glasing steps:

1. The AFP FM-200) throttle body. Front of FM-200 is about 1 3/8" further forward than the FM-150 and 9/16" greater inside throat radius (Bendix type):


2. The Bendix style (AFP FM-150) throttle body:


3. Snorkel in place after trimming off the snorkel Bendix flange and positioned in front of the FM-200; marked centerline of the FM-200. Note how the lower lip if the FM-200 is below the snorkel edge:


4. Preliminary positioned glased ring into snorkel, approximated after snorkel in position on the engine (lots of incremental steps positioning to get to this point); glased ring is interior and exterior diameter of the FM-200 throat and 1 3/4"+/1 long. Note the blue mark on snorkel > the approx line on the forward rim of the FM-200 - the edge of the ring will end up being about 1/8" clear of the forward rim of FM-200:


5. Will be cutting the bottom of the snorkel out to the largest cut-out line (and then some as I progressed):


Next post with 5 more pics>>
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Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47

Last edited by jeffw@sc47 : 10-26-2017 at 03:57 PM.
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  #15  
Old 10-22-2017, 09:30 AM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
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6. Positioned snorkel with fingers cut into bottom of snorkel. I had to abandon the 'fingers' mod because these fingers flattened out and eliminated the nice bottom buldge of the snorkel (taking out a lot of the volume of the snorkel). Had cut out the whole bottom to build in length-wise ribs of SS rod, tacked with super glue, repositioned many times to get proper alignment to FM-200.


7. Snorkel with fingers cut into top of snorkel. These were bent down to the top of the glas ring, and tacked with super glue, repositioned many times to get proper alignment to FM-200. Eventually glased to the ring; as they were bent down, their ends came forward to the forward edge of the glas ring.


8. Bottom of snorkel completely cut out and ribs tacked onfor shapoe of buldge.


9. Early positioning alignment - note how the glas ring is not well aligned with FM-200 throat. Had to pop off rib ends and re-super glue a number of times to get the alignment right on.


10. Middle portion of snorkel has been cut out and has a few glas longitudinal ribs tacked on. I order to take out a twist in the snorkel body between the two ends I had to eventually do this. You may find no twist or a better way to do this. I first tried cutting some lateral cuts to make the snorkel 'accordian' to take the twist out but that did not work like I thought it would.


From here on, the process is many attachments to engine, un-tack stuff, re-tack stuff, twist and tug, then many small glasing patches of the openings in steps that allowed me to get to the inside of the snorkel as much as possible and to let the patches of glas to hang via gravity to form as much as possible rounded patch forms rather than faceted patches.

This is the orientation of the throttle body on the engine; it has to be this way because there is a sensing port on the stem (small hole just to the left of the center cone) that has something to do with regulating the fuel flow (from my memory of an explanation by Don Rivera). If that port is on the opposite side close to the sharp bend of air around the last turn of the snorkel into the throttle body, the fuel flow goes way down.


Here is the snorkel hanging on the engine.


The snorkel is attached to the throttle body with a 1 1/4" long x 3 1/2" I.D. piece of silicon reinforced hose (race car type used in the super charger zone). Bought a short piece on line from K&N (kandn.com); Cut it to short pieces on a metal cutting band saw. Stainless hose clamps (No. 60, 4" Dia) on throttle body and snorkel ends.
__________________
Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47

Last edited by jeffw@sc47 : 10-22-2017 at 03:01 PM.
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