Relentless update ...

[comancheflyer]

Just stopped by the Relentless cave and chatted with Kevin for a quick second. He says the plane is ready to go with a geared GTSIO-520 Continental with dual turbos and a 4 blade MT prop. Looks real nice! Of course I did not have my camera to steal any photos - dang it. I'll remember to bring my camera tomorrow and see if I can sneak some photos for all you meaniacs.

[supercub]

Re: Relentless update ...

Can you go back and get some pictures? Can't wait to see that.
Brian

[Donald McMullin]

Re: Relentless update ...

Titan Engine web page referenced Kenin's engine as a GTSIO-550 which is extremely rare, is it a more common geared 520 or an actual geared 550??

[comancheflyer]

Re: Relentless update ...

Titan Engine web page referenced Kenin's engine as a GTSIO-550 which is extremely rare, is it a more common geared 520 or an actual geared 550??

I asked him 'like the one in a 421 Cessna' and he confirmed it. Not sure if it has bigger cylinders or not, I'll try and get more info tomorrow. Seems like a good power plant to use with the gearing down to slow the prop. The stock gear reduction of a 520 is 2.3 to 1 apparently. If the prop spins say 2700 or so rpm, that engine will be singing around 6200 rpm.

[Donald McMullin]

Re: Relentless update ...

Just curious if Kevin had come up with 5.40 inch bore cylinders to mate with 4.00 inch (520 crank) to come up with 550 in3.

Standard GTSIO-520 reduction is 0.667:1.0, so at rated 3400 (engine) rpm the prop is turning at 2,270 rpm. However there was a gear reduction (C model) at 0.750:1 which would result in prop turning at 2,550 rpm.

[N22252]

Re: Relentless update ...

...and this stuff is why the Sport Class is poised to be the new home of excitement in air racing....

Gear reduction... Check
Large bore cylinders... Check
Forced Induction...Check
The best, and rarest parts out of the catalog...Check
400 MPH... you ain't seen nuthin' yet.

[supercub]

Re: Relentless update ...

Can't wait

[Arctic Cat]

Re: Relentless update ...

...and this stuff is why the Sport Class is poised to be the new home of excitement in air racing....

Gear reduction... Check
Large bore cylinders... Check
Forced Induction...Check
The best, and rarest parts out of the catalog...Check
400 MPH... you ain't seen nuthin' yet.

Don't forget programmable electronic fuel injection and electronic ignition

[Race5]

Re: Relentless update ...

Just curious if Kevin had come up with 5.40 inch bore cylinders to mate with 4.00 inch (520 crank) to come up with 550 in3.

Standard GTSIO-520 reduction is 0.667:1.0, so at rated 3400 (engine) rpm the prop is turning at 2,270 rpm. However there was a gear reduction (C model) at 0.750:1 which would result in prop turning at 2,550 rpm.

Kevin's new business venture has been building new design cylinders for several applications. It would not surprise me one bit for him to have some prototype parts on the race engine.

[Fence Sence]

Re: Relentless update ...

Kevin's new business venture has been building new design cylinders for several applications. It would not surprise me one bit for him to have some prototype parts on the race engine.

Win on Sunday, sell on Monday.

[comancheflyer]

Finally got some pictures from the Relentless cave last night ...

Kevin and his helpers were busy wrenching heavily last night getting Relentless ready, so I wasn't able to ask too many questions. Interesting that he's not running any kind of charge cooler but I suspect he is using some sort of water injection to keep the air/fuel mixture cool? Turbo chargers are look pretty dang big to me. I cannot confirm it, but I think he is running a 'cold air kit' too.

[tuffer]

Re: Relentless update ...

Nice pictures dude

mot

[comancheflyer]

Re: Relentless update ...

Cowling is together and on and Kevin ran it up some on the ramp last night - sounded very very healthy. Cowling finish is a little rough if you look at it up close, but as Kevin quoted: "I don't think anybody will notice at 400 mph"

Says he plans on arriving Friday ...

[comancheflyer]

Re: Relentless update ...

Just left KSBP airport this evening after working on my plane and noticed that Relentless was back in her hanger with the cowling off. Hopefully a minor issue that can be solved in time. Let the drama begin ... (as if it hasn't already)

[Race5]

Re: Relentless update ...

Just left KSBP airport this evening after working on my plane and noticed that Relentless was back in her hanger with the cowling off. Hopefully a minor issue that can be solved in time. Let the drama begin ... (as if it hasn't already)

Motor let go on the second test flight. They are not coming.