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  #21  
Old 06-25-2018, 05:42 PM
crabandy crabandy is offline
 
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Quote:
Originally Posted by DanH View Post
Or just forget about it. The oil temps are great, with the oil door closed. CHTs apparently not an issue. The best cure for poor idle due to temperature is generally twofold; higher energy ignition, and reduce heating of the carb and fuel lines. I suspect most of that heating is radiant, so just blowing more air through the cowl is not gonna to get 'er done.
My issue isn’t poor idle, it’s lack of idle and running in general. On 95* day quick turns I’ve had it quit on me (more than once) (leaned mixture, idling 1200 rpm etc) and had to radio the tower while I let it cool down and wave as the airline passengers taxi by watching me pull my airplane to the edge of the taxi way, talk about embarrassing. Also on the long taxi into OSH, and the last solar eclipse I barely made it off the runway....

CHT’s and Oil Temps are always easily within limits, I think it is radiant heating of the carb. It generally starts surging while on the idle circuit around 600 rpm, if I ride the brakes and taxi at 1000-1100 rpm it does ok for a period. If it does surge and die I’ve found the flooded start procedure works as long as I run it on the main jet at higher RPMS. Not sure I can protect the carb from radiant heating.

The fuel systems is Van’s plan with the gascolator and red cube, I have a heat shield on the exhaust from the red cube to the carb.

I’ve thought about a cooling shroud for the fuel pump, but with no pressure diff on the ground it does no good.

Remove the Gascolator? Probably help but maybe not solve.

With the stock Van’s cowling I used to see heat rising/leaking out the inlets and around the spinner after a hot shutdown. After my rubber boot inlets-plenum-crankshaft-spinner seal I no longer see this. I see it when I open my oil door though.
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  #22  
Old 06-25-2018, 06:21 PM
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DanH DanH is offline
 
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Andy, your under-cowl air temperatures are not likely to be warmer than those found under any other cowl, roughly 125F to about 240F localized in the baffle opening right under hot cylinder. We can measure it if you want.

Got photos? Let's look at the radiant heating situation.
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  #23  
Old 06-25-2018, 06:59 PM
crabandy crabandy is offline
 
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I just re-cowled after the oil change and away from the airplane, lemme dig through some photos.

Lower cowl temps aft of the accessory case away from any cylinder hit 215-220 *F on a 95* quick turn, seems to be when I have trouble. I havenít measured next to the carb yet.
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  #24  
Old 06-25-2018, 07:24 PM
VIN2020 VIN2020 is offline
 
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Quote:
Originally Posted by PerfTech View Post
….We have had many customers mount our cowl flaps on the sides of the lower cowl as well as on the top. They report back many advantages, Lower ground operations temperature being one. Another is even lower climb out temperatures, due to the fact that the pressure in this configuration is much lower on top than on the bottom. We have seen most everything possible with flaps on top, sides, bottom and all of the above in one installation. The top mounted location is very popular in Brazil on the RV-10s. Its all good!
Thanks, Allan..

Allan
Please post pictures of those side and top mounted doors.
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  #25  
Old 06-25-2018, 08:04 PM
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Raymo Raymo is offline
 
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Quote:
Originally Posted by crabandy View Post
Mikey,
Iím carbureted with dual electronic ignition and auto plugs, I think the fuel is boiling in my carb bowl....
I think the fuel is getting hot before it gets to the carb, where it gets hotter. You might try putting a phenolic block or similar insulator between the carb and sump to insulate it from the block heat.

You haven't mentioned if turning on the boost pump helps. If not, your "boiling in the bowl" theory sounds more feasible. Also, that gascolator is likely part of the problem, heating the fuel before it gets to the carb.
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  #26  
Old 06-25-2018, 08:43 PM
SJordan SJordan is offline
 
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Honestly I did not read all three pages of posts but I LOVE MY COWL FLAP! Just built a -4 with a 200hp 360 and with my cowl flap open I can takeoff from DVT at 1,500ft and 108deg out and climb at 1,500fpm to 17,500ft and never break 400 CHT.
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  #27  
Old 06-26-2018, 09:24 AM
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PerfTech PerfTech is offline
 
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Quote:
Originally Posted by VIN2020 View Post
Allan
Please post pictures of those side and top mounted doors.
...Here are some photos of one guys RV-10 installation and I will try to find others
when I get on my other computer. His are a bit further forward than most we have
seen, but will work very well in this local as well. Thanks, Allan.











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  #28  
Old 06-26-2018, 02:27 PM
Turbo69bird Turbo69bird is offline
 
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Allan thanks for the pics of the 10install would like to put in a request for RV6 pics. as well 😀👍
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  #29  
Old 06-27-2018, 09:19 AM
crabandy crabandy is offline
 
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Finally took some recent pics, basic Van's system with Vetterman crossover exhaust. Inline screen fuel filter after the fuel selector to the facet fuel pump.

Gascolator to engine fuel pump







Engine fuel pump to red cube





Mostly likely source for Radiant heating of the carb and fuel line.....it has the stock Van's heat shield.





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Last edited by crabandy : 06-27-2018 at 09:26 AM.
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  #30  
Old 06-27-2018, 09:31 AM
crabandy crabandy is offline
 
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Quote:
Originally Posted by Raymo View Post
I think the fuel is getting hot before it gets to the carb, where it gets hotter. You might try putting a phenolic block or similar insulator between the carb and sump to insulate it from the block heat.

You haven't mentioned if turning on the boost pump helps. If not, your "boiling in the bowl" theory sounds more feasible. Also, that gascolator is likely part of the problem, heating the fuel before it gets to the carb.
Boost pump generally doesn't help when very heat soaked, It clicks loudly like there is no fuel. Sometimes it helps if it is only marginally heat soaked.
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