Sprint100
Well-Known Member
I found this email from a guy I met online during my initial research into rotary engines. I remember killbilly asking about rotary engines and I was going to send him this via PM but decided to post it for all to view...
Hi,
I'm pretty happy with my rotary. I'm currently working with another builder to complete his rotary install, following my proven layout very closely.
Have I had more problems than normal? Certainly the install took way longer than a Lycoming would have. You can read the detail on my web site (http://canardaviation.com/cozy ). There's really no "normal" for putting rotary in a Cozy, and I had a fairly steep learning curve with very few examples to follow. I think the state of the art has progressed and installing a rotary is easier now.
Is it worth doing? The short answer is yes... if you have the determination required to do the work. Engine mounts are available now, but you'll still need to fabricate a custom intake and cooling system.
My original decision to install a rotary was, believe it or not, based on safety considerations. There's no doubt that initial testing was a bit risky, but once the bugs are out of the peripherals, the reliability of the core engine comes into play - its real hard to break these things, and even when they do fail they usually keep running long enough to get you home. By contrast, when a Lycoming fails it often does so catastrophically leaving you instantly with a glider.
Every rotary installation is a one-off and, as such, there are many things that can bite. We cover ourselves with lots of redundancy e.g. duel fuel pumps, injectors, batteries, ECUs, spark plugs, coils, even fuel delivery systems. Redundancy of all these items allows continued flight even when something fails, but also adds considerable complexity and pilot workload.
It took me about a year (on top of 4 years to build the Cozy) to create the rotary installation, and about another year to test it.
I get about 250HP with my turbo 13-b rew. One main advantage of all that power is take-off distance and initial climb rate.
I once took it up to the plans VNE of 190 kts straight & level at 11,000 feet. (I had plenty of throttle travel left). That equated to 269 MPH triangulated ground speed. Typical cruise is closer to 200 MPH because fuel consumption goes up rapidly with increased speed. That's not a failure of the rotary - just a fact of nature.
Oil and coolant temperatures stabilize at around 210F while taxiing on a 90F day. I usually don't use full power for take-off, and on a hot day it's necessary to back off the power and do a "cool off" pattern before climbing out. That was a design trade-off decision - it's better to have slightly marginal cooling on a very hot day than increased drag and reduced efficiency / top speed due to excessive cooling drag. On a cold day here in Connecticut take-off is nothing short of exhilarating, even on half throttle.
If you decide to do it I have a few suggestions:
1. Forget about the engine until you have a fuselage on gear, wings and canard built.
2. Visit and look closely at as many flying rotary engine installations as you can find.
3. Go to Rough-river in 2009
4. Join the fly-rotary mail list
4. Beware of advice from a self-professed expert (who has never actually flown a rotary) named Paul Lamar.
If you have further questions, feel free to ask them on the forum where all readers can benefit from the answers.
Regards,
John
Hi,
I'm pretty happy with my rotary. I'm currently working with another builder to complete his rotary install, following my proven layout very closely.
Have I had more problems than normal? Certainly the install took way longer than a Lycoming would have. You can read the detail on my web site (http://canardaviation.com/cozy ). There's really no "normal" for putting rotary in a Cozy, and I had a fairly steep learning curve with very few examples to follow. I think the state of the art has progressed and installing a rotary is easier now.
Is it worth doing? The short answer is yes... if you have the determination required to do the work. Engine mounts are available now, but you'll still need to fabricate a custom intake and cooling system.
My original decision to install a rotary was, believe it or not, based on safety considerations. There's no doubt that initial testing was a bit risky, but once the bugs are out of the peripherals, the reliability of the core engine comes into play - its real hard to break these things, and even when they do fail they usually keep running long enough to get you home. By contrast, when a Lycoming fails it often does so catastrophically leaving you instantly with a glider.
Every rotary installation is a one-off and, as such, there are many things that can bite. We cover ourselves with lots of redundancy e.g. duel fuel pumps, injectors, batteries, ECUs, spark plugs, coils, even fuel delivery systems. Redundancy of all these items allows continued flight even when something fails, but also adds considerable complexity and pilot workload.
It took me about a year (on top of 4 years to build the Cozy) to create the rotary installation, and about another year to test it.
I get about 250HP with my turbo 13-b rew. One main advantage of all that power is take-off distance and initial climb rate.
I once took it up to the plans VNE of 190 kts straight & level at 11,000 feet. (I had plenty of throttle travel left). That equated to 269 MPH triangulated ground speed. Typical cruise is closer to 200 MPH because fuel consumption goes up rapidly with increased speed. That's not a failure of the rotary - just a fact of nature.
Oil and coolant temperatures stabilize at around 210F while taxiing on a 90F day. I usually don't use full power for take-off, and on a hot day it's necessary to back off the power and do a "cool off" pattern before climbing out. That was a design trade-off decision - it's better to have slightly marginal cooling on a very hot day than increased drag and reduced efficiency / top speed due to excessive cooling drag. On a cold day here in Connecticut take-off is nothing short of exhilarating, even on half throttle.
If you decide to do it I have a few suggestions:
1. Forget about the engine until you have a fuselage on gear, wings and canard built.
2. Visit and look closely at as many flying rotary engine installations as you can find.
3. Go to Rough-river in 2009
4. Join the fly-rotary mail list
4. Beware of advice from a self-professed expert (who has never actually flown a rotary) named Paul Lamar.
If you have further questions, feel free to ask them on the forum where all readers can benefit from the answers.
Regards,
John
