RV-7A with Rotary "Renesis" 13B

[dlomheim]

I purchased an RV-7A the end of Sept. and then took 30 days to meet insurance requirements, but finally got it home. I then spent the next month making it airworthy (brakes, tires, oil, etc.), and have now finally begun getting to know it a bit. Since I've been building a 9A with a 13B since 1999 (#90116), it's nice to have this 7A rotary to fly, while I finish building the 9A! Empty weight: 1107 lbs., est. HP 180, Prop: Cato 76X88, Total Time: 928 hrs., PSRU: Tracy Crook's "C" model w/2.85 ratio, fuel: 87 oct. auto fuel with 1.5 ounces of marvel mystery and 1.5 ounces 2 cycle oil added per 5 gallons of fuel. Cruises 175 TAS at 7-8K, and est. 8.5-9.5 gph. As I fly it more, I'll be able to get some updated numbers.

Doug

RV-7A w/RX-8 13B Flying
RV-9A w/RX-7 13B FWF
RV-3A w/O-290"G" sold

 

[PilotjohnS]

Sounds like a good plane, may you enjoy it forever

 

[dlomheim]

I now have flown the Renesis powered RV-7A I purchased last Sept for about 13.5 hrs. with a 4.0 logged yesterday. Over the 4.0 hrs. I burned an avg. of 8.5 gph while cruising about 160 mph TAS, at 5500 ft. Thus far the engine fires up every time after only turning 1-1.5 blades, whether hot or cold. The oil is running a higher than I'd like in climb out (@210 degrees), but it drops down to 185 degrees while cruising. I still am going to experiment by adding a "shark" like air exits on the oil cooler side of the cowling, or possible add a turning vane to the intake to pull some more air from the water radiator side, since water runs cool at 145 degrees on a regular basis.
If you're looking for a nice airport restaurant in KS, check out the Lloyd Stearman Field restaurant, on the north end of the airport.

 

[JonJay]

Doritos powered! Now that’s experimental

 

[dlomheim]

I've been flying the RV-7A fairly regularly since January and finally hit 50 hrs. on the hobbs meter, and therefore pulled the cowling off and drained the Mobile One oil. The Renesis 13B lost/burned zero (0) oil over the last 50 hrs., and visual of everything under "the hood" looked pretty good, and no worse for wear owing to the 963 hrs. now on this installation.

Since the cowling was off I also did a compression test on both rotors which yielded 88 95 89 (#1), and 89 92 91 (#2), and as a rule of thumb (on rotaries), 80+ PSI shows the engine is still pretty tight and producing good HP.

Doug

 

[chaskuss]

snipped since water runs cool at 145 degrees on a regular basis. snipped

145 degrees for coolant temp is considerably below what Mazda designed the cooling system to run at. Any concerns there? Are you using a thermostat in the cooling system?

 

[Gearhead51]

I like reading this as I was a Rotary specialist in the 90's. Some day I may go for it, but for now, I'll live vicariously through you.

 

[dlomheim]

145 degrees for coolant temp is considerably below what Mazda designed the cooling system to run at. Any concerns there? Are you using a thermostat in the cooling system?

This installation now has 965 hrs. and has thus far shown no ill effects of slightly cooler water temps. I am looking for a water/oil intercooler to install this winter which would better narrow the gap between water/oil temps; according to those who have done that on their installations.

 

[dlomheim]

A buddy from Colorado stopped by with his RV-8A powered by a "Powersport" 215 hp Rotary 13B engine. It's not too often when two flying rotary powered RV's get together!

 

[skirting_virga]

A buddy from Colorado stopped by with his RV-8A powered by a "Powersport" 215 hp Rotary 13B engine. It's not too often when two flying rotary powered RV's get together!

There's a rotary powered 8A in CO? I'd love an introduction!

 

[lr172]

. I burned an avg. of 8.5 gph while cruising about 160 mph TAS, at 5500 ft.

is this typical of the 13b in an rv?

 

[dlomheim]

is this typical of the 13b in an rv?

It is fairly typical from what I've learned from others flying RV's with the 13B / Renesis installations. Most have reported they can cruise between 7.5 and 9.5K feet at 160-165 mph with a fuel burn between 8-9 GPH, depending on how aggressively their particular installation will allow them to lean.

 

[lr172]

It is fairly typical from what I've learned from others flying RV's with the 13B / Renesis installations. Most have reported they can cruise between 7.5 and 9.5K feet at 160-165 mph with a fuel burn between 8-9 GPH, depending on how aggressively their particular installation will allow them to lean.

Thanks

 

[dlomheim]

It is fairly typical from what I've learned from others flying RV's with the 13B / Renesis installations. Most have reported they can cruise between 7.5 and 9.5K feet at 160-165 mph with a fuel burn between 8-9 GPH, depending on how aggressively their particular installation will allow them to lean.

Additional data point: From 5/10-9/27 I burned 358 gallons and flew 42.9 hrs. = 8.3 GPH of 87 E10 fuel from Sams (avg. $2.359 / gallon). I also pre-mix 1.5 ounces of marvel mystery and 1.5 ounces of 2 cycle oil per 5 gallon jug, so that is an additional cost over and above the fuel purchases. My normal cruising speed is 150-155 mph TAS. I hope to knock out some higher altitude cross country trips in the future to see how efficient it is (or not) at 10-13K.

 

[QuickBuild_SlowPilot]

Hi Doug, I’m new here. That 7A sounds amazing! Really cool to see the numbers and hear how it flies. Hope to learn a lot from posts like yours!

 

[dlomheim]

Uploaded my video of the RV-8A takeoff with "Powersport" 215 hp with MT taking off on my u-tube channel ...very impressive performance with the MT!

 

[dlomheim]

After buying this 7A last Sept and flying it home, oil temps have been something that required constant management since the red line for rotaries is about 215 degrees. On 95+ degree Oklahoma days, I consistently had to reduce power to 20-21 inches and climb at 120+ mph, until dropping OAT allowed temps to fall below 205, etc. Since the a/c is currently down for its' annual condition inspection, and I recently obtained an oil cooler off of an IO-360, I decided to install that in series after the stock Mazda cooler and see what help that might provide. Fortunately I had a large open area on the plugs side of the engine bay, so installed the cooler there and used modeling clay to fashion a plenum to accept a 2 inch SCAT tube. Also added a scoop through the cowling and connected it all up and performed a :15 ground run. That short run with a few minutes at WOT showed an oil temp drop of 15-20 degrees, with a high of only 160 degrees where as before I would have already been up to 180. Once the condition inspection is finished I'll perform an initial flight test and validate final temp improvement (or not).

 

[dlomheim]

Fun flight today from OK City to Wichita and the "Stearman Field", where they have a nice restaurant on the north end. On the trip home the RV-7A turned over 1,000 hrs. on the hobbs of "rotary" powered engine time; which was a great accomplishment by the original builder (Dennis Haverlah); who first flew it in 2007. Zoom-zoom!

Doug

RV-7A Mazda Renesis
RV-9A Project (Converting from Mazda 13B to Superior IO-360...

 

[airguy]

Very few auto conversions reach 1000 hours, that is certainly a milestone. Most fall prey to either cooling or gearbox issues before then.