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-   -   ASA New Product Video is up! (July 2014) (https://vansairforce.net/community/showthread.php?t=115072)

BillL 07-17-2014 09:53 AM

Quote:

Originally Posted by PerfTech (Post 897700)
....Here are the pressure differential numbers we gathered on my airplane (RV-9A). These percentages of increases were typical of what was gathered on all the other tests aircraft with stock Vans factory cowl. We installed a second unit and tested the improvement as many people were ordering two and ask for this differential information.
.

.:D

Alan, you have elevated your game by generating data and providing to this forum!! Thanks. A curious question, and surely you asked your self too, why the disparity of pressure from one and +1 open flaps? Was one better located than the other? If so it would give some quantification to the airflow chaos under the lower cowl.

rvator51 07-17-2014 12:40 PM

Thanks Brian,
Wish I had read your post before I cut my opening because I have the same gap at the hinge as you do.

For the RV4 cowl, its only about 0.70 thick as it isnt honeycombed on the bottom. So the cowl flap sticks out at the bottom a lot.



I had to make a .125 shim all of the way around.



My cowl flap still sticks out about .050 so I need to increase the .125 shim to .175 to get it flush.




I used 6/32 screws temporally until I decide what the final configuration will be.


PerfTech 07-17-2014 01:14 PM

Quote:

Originally Posted by BillL (Post 898466)
Alan, you have elevated your game by generating data and providing to this forum!! Thanks. A curious question, and surely you asked your self too, why the disparity of pressure from one and +1 open flaps? Was one better located than the other? If so it would give some quantification to the airflow chaos under the lower cowl.

...That was a good question! I just took the RV-9A back up as instrumentation was still installed. Got the same result, so I opened the other side first and got almost identical numbers. Answer to the question, don't know!...:confused:

PerfTech 07-17-2014 01:27 PM

Quote:

Originally Posted by rvator51 (Post 898525)
Thanks Brian,
Wish I had read your post before I cut my opening because I have the same gap at the hinge as you do.

For the RV4 cowl, its only about 0.70 thick as it isnt honeycombed on the bottom. So the cowl flap sticks out at the bottom a lot.



I had to make a .125 shim all of the way around.



My cowl flap still sticks out about .050 so I need to increase the .125 shim to .175 to get it flush.




I used 6/32 screws temporally until I decide what the final configuration will be.


... Sorry you had some difficulty with the thickness at .250". That is the thickness of most of the cowls and we had to pick something. I should have put in the instructions that a shim was required on the early cowl configuration. Perhaps on the next run we can laser out some shims for this purpose so it will be easier for the next guy. Thanks, Allan...:D

rvator51 07-18-2014 11:28 AM

Cowl flap is wired up now. I put the switch and the led just above the flap switch.







I will flight test it tomorrow.

moll780 07-18-2014 12:31 PM

how did do the connector/connection for cowl removal?

I have mine on order!

rvator51 07-18-2014 12:47 PM

The kit included two sets of wires. I ran one from the servo up the side of the bottom cowl and covered it with aluminum tape to hold it in place.
The other set of wires is ran from the switch through the firewall and just used the supplied connector (someone said they were RC connectors) to connect to the wire from the servo and attached a standoff from my battery cover to hold them in place. I may change the connectors to a molex connector in the future. A side benefit now is that if the cowl flap is down for taxiing in, you will have a blinking light on the panel to remind you to turn the master switch off.


dealfair 07-18-2014 08:25 PM

Many thanks Brian & Thomas for posting your install. :)

Brantel 07-19-2014 07:45 PM

After running a 10K race in the pouring rain this morning, I changed the oil, finished the switch/wiring/led install for the cowl flaps (used a 2 pin molex plug for the disconnect), made another radiant heat shield for the non heat muff side of the exhaust, changed out some non-aircraft grade cushion clamps that were turning to goo and put the cowl on and took her for a spin.

I forgot to take one with em closed....sorry!







Too early to tell but I can say that I can already see a difference in CHT's during a hi performance climb. The cloud deck was not that high so I could not get a true test but the initial temps are promising.

I don't want to post numbers until I can go out and do some climbs with em open vs shut in similar atmospheric conditions. To do otherwise will just be a WAG and not very meaningful.

Straight and level in cruise @ 4300ft I am seeing a change of about 3 knots TAS open vs closed. The sound from the engine area changes when they are open.

Had the best wheel landing I have ever pulled off tonight. Too bad there was nobody there to see it!

PerfTech 07-21-2014 10:34 PM

Temperature Improvements?
 
...We received many e-mails and phone calls asking for information as to the difference in climb temperatures we encountered on climb outs. I am very reluctant to say this will do "this" when it comes to temperature problems as the root causes can be any number of, or a combination of several things. That being said, I went out this last weekend to do some testing with temperature being the only parameter looked at. With the engine fully warmed up, I performed nine climbs to altitude, at three different climb speeds, 80 kts, 100 kts and 120 kts all starting at 1,500' and terminating at 8,500'. Each speed first with EZ Cool flaps closed, then with one open, then with both open. The results were as follows;
....80 kts closed= peak 430 deg. one open = 419 deg two open = 407 deg.
..100 kts closed= peak 424 deg. one open = 407 deg two open = 396 deg.
..120 kts closed= peak 416 deg. one open = 397 deg two open = 387 deg.
The outside air temperature here in So Cal was a hot and muggy high 80s during the tests. Everything full foreword, at 2,750 rpm working the engine as hard as possible. None of this is chiseled in stone, and others results may vary. As a reference point, this was what I saw and was very repeatable for me. I didn't notice any speed penalty at these low speeds but did see about three kts reduction at 180 kts after opening both cowl flaps and letting it all settle down. Thanks, Allan...:D


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