sandbag23(at)msn.com
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 Posted: Tue Jun 01, 2010 6:48 am Post subject: Initial AuCountry "Jaguar" cowl report |
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.ExternalClass .ecxhmmessage P {padding:0px;} .ExternalClass body.ecxhmmessage {font-size:10pt;font-family:Verdana;} Tiger N119ST now has a few flights with the STC/PMA Gary Vogt cowl (which includes previously installed Powerflow short stack). Keep in mind this '76 airframe with significant damage history was, oddly, considered "fast" before the install. It carried 8 months of ramp grime during these flights, and the prop is due for an overhaul. It doesn't have a tail beacon or steps, is well rigged, and has the K&N air filter STC. These initial tests are by no means scientific, but you might be interested in some numbers:
1950lbs GW, forward CG
2500ft PA
15degC OAT
Full throttle, moderate lean
2700+ RPM (mechanical tach clocked accurate, 63" Sensenich)
143 KIAS
149 KTAS
This was the first flight for plane and pilot in 8 months in rough air. The prop wanted to overspeed with every bump. First impressions were that there was more speed and better cooling, but I couldn't quantify in the short time spent renewing landing currency.
2000lbs GW, fwd CG
11,500ft PA
12,090ft DA
0degC OAT
Full throttle, max lean (by sound), 9.4gph
2615 RPM
120 KIAS
144 KTAS
Max EGT #1 1460degF
Max CHT #4 385degF
Oil Temp 178degF
1950lbs GW, fwd CG
13,500ft PA
15,100ft DA
-5degC OAT
Full throttle, max lean (by sound), 8.2gph
2600 RPM
114 KIAS
144 KTAS
Max EGT #1 1420degF
Max CHT #3&4 381degF
Oil Temp 178degF
These flight were in smooth air. The impressive numbers may be misleading because of the low OAT; in similar conditions I used to run my hottest CHT around 400deg F.
On a short family hop, max gross with an aft CG (but still not washed), it was pushing 150 KTAS at 3500ft before my wife asked the benefit of red-lining on our first flight, overwater, in 9 months.
So overall I think it's safe to say that I've gained more than 5 kts in my normal mode of mid altitude, throttled back, aggressively leaned economy cruise; from roughly 135KTAS to 140KTAS. Cylinders temps are more closely matched, with #1&2 running maybe slightly hotter and #3&4 cooler than they used to in all phases. During one full rich, 100KIAS climb on a 70deg F day #1 went over 440degF where usually #3 or #4 would have been there first. Oil temps appear the same as with the original cowl and Powerflow (which increased oil temps by around 15degF).
My original cowl was significantly damaged, patched, debonded and Bondo'd, so the main goal of this purchase was a hardware replacement. The appearance (still needs paint to match; I've already witnessed 2 lookie-loos inspecting the conspicuous nose), speed and cooling benefits are gravy. When I download the EDM-700 we'll have some quantifiable before and after temperature results.
-Brian
N119ST (at) KSDM Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox. Learn more. [quote][b]
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