David-aviator
Well Known Member
I took the H6 (normal aspiration) up to 11,500 on a 4.9 hour round robin to Nebraska from St. Louis yesterday. Here are some numbers and observations regarding the flight.
It seems the MT prop works best at 2500 rpm in climb. Also, 90 KIAS appears a best climb rate speed up high although I have become accustomed to a cruise climb configuration of 2300/110K at low altitude. The airplane was climbing steady at 600 fpm through 11,000.
Once level, after trying several different rpm settings, I let it roll at 2200 rpm. Even after some 2 years with this engine/prop combination, I still haven't figured out the best configurations at various altitudes for speed and fuel flow.
Prop RPM 2200 (engine 4036)
Manifold Pressure 19.1 (WOT)
Fuel Flow 6.4 gph
OAT 35F
TAS 140 knots (Dynon computation)
(The Dynon IAS is about 3 knots less than Van's IAS so TAS is
conservative.)
Total burn for the trip was about 33 gallons with 4.9 on the Hobbs.
Note: this is the #1 H6 installed in an RV. The EGG factory has improved the engine/prop combination considerably with turbo charging and a 4 blade Sensinich/Quinti prop.
Cabin heat was very comfy. We use a 3 speed fan to extract heat from a small radiator on the aft side of the fire wall. It works quite well. I did use a blanket for the upper body half due to much canopy air leakage but there was plenty of heat from under the IP running the fan at mid speed. The worst source of cold air is from the aileron push tube holes into the wing. That air comes up through the stick cut out and is on a list of things to improve.
The EGG factory has an informal deal with flying Subbys to inspect on going projects. That was the purpose of the trip. This Nebraska 9A with a 2.5 engine is of excellent quality and should be flying soon.
It seems the MT prop works best at 2500 rpm in climb. Also, 90 KIAS appears a best climb rate speed up high although I have become accustomed to a cruise climb configuration of 2300/110K at low altitude. The airplane was climbing steady at 600 fpm through 11,000.
Once level, after trying several different rpm settings, I let it roll at 2200 rpm. Even after some 2 years with this engine/prop combination, I still haven't figured out the best configurations at various altitudes for speed and fuel flow.
Prop RPM 2200 (engine 4036)
Manifold Pressure 19.1 (WOT)
Fuel Flow 6.4 gph
OAT 35F
TAS 140 knots (Dynon computation)
(The Dynon IAS is about 3 knots less than Van's IAS so TAS is
conservative.)
Total burn for the trip was about 33 gallons with 4.9 on the Hobbs.
Note: this is the #1 H6 installed in an RV. The EGG factory has improved the engine/prop combination considerably with turbo charging and a 4 blade Sensinich/Quinti prop.
Cabin heat was very comfy. We use a 3 speed fan to extract heat from a small radiator on the aft side of the fire wall. It works quite well. I did use a blanket for the upper body half due to much canopy air leakage but there was plenty of heat from under the IP running the fan at mid speed. The worst source of cold air is from the aileron push tube holes into the wing. That air comes up through the stick cut out and is on a list of things to improve.
The EGG factory has an informal deal with flying Subbys to inspect on going projects. That was the purpose of the trip. This Nebraska 9A with a 2.5 engine is of excellent quality and should be flying soon.