P85 - A New Aircraft

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Jeffd

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After a much hotter than normal month of June here in the Kansas City area, finally cooled down a bit so I enjoyed an evening cruise around the local area in the P85. Continuing to build flight time on the V8 whenever possible.

An advantage of the pointed cowl shape is good forward and down visibility over the nose:

DSC00492 resized.jpg

Over the nose.jpg

Jeff
 

rv6ejguy

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After a much hotter than normal month of June here in the Kansas City area, finally cooled down a bit so I enjoyed an evening cruise around the local area in the P85. Continuing to build flight time on the V8 whenever possible.

An advantage of the pointed cowl shape is good forward and down visibility over the nose:

View attachment 52392

View attachment 52391

Jeff
Sure like the looks of V8 nose...
 

Toobuilder

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OK. Where are we at with the P85 Program? Heard the airplane was for sale... what's the scoop?
 

rv6ejguy

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Yup, airplane was for sale last month. Some changes in the company has focused future work in other directions. Jeff will add more details if appropriate.
 

Toobuilder

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"Other directions"... Hopefully that doesnt turn out to be turning their back on the V-8 in favor of a turbine like the Legend!

We desperately need a "win" in the turn key V-8 aircraft market. My hopes were dashed with the Legend saga, and If the P-85 gets dropped....

I'm just not sure how many more times I can be hurt!

Their website looks like a ghost town - "latest news" is from August!
 

rv6ejguy

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I always thought the P85 was a great concept compared to a Radial Rocket and it seemed to have a very trouble-free development, probably thanks to Jeff's previous experience with the V8 Legend.

If you could just plug in a crate LS3 or LS376 to the Ballistic drive, it's amazingly cheap compared to IO-540s or M14P engines and outperforms them both plus both parts are US made and readily available.

I certainly wouldn't mind a P85 in my hangar...
 

Jeffd

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Hey everybody, here's the "scoop"-

After many. many years of being heavily involved in the kit aircraft industry it is now time for me roll back my work schedule and semi-retire, at least. That means time to sell rights to our aircraft designs and the prototype P85. I say "semi-retire" because the handful of potential purchasers I have been in discussions with to date all require my continued participation to some degree, something I am happy to do. I don't fish or golf, so I would be out at the hangar building another airplane anyway! Just time to reduce the level of task saturation.

One option would be for me to hang onto the P85 prototype, allowing a new kit operation owner to put that capital into another demonstrator aircraft. I would enjoy finishing the paint/interior on the P85 and rack up the flight hours, on a less task-saturated basis. Toobuilder, don't worry! - the P85 won't be dropped. Current LS engine tech makes Big block Chevy engine in the Legend crude by comparison. Based on experience to date with the P85, turn key firewall forward installations would not be difficult - just takes some man hours and energy. The LS engine installation in the P85 is really quite simple and straightforward, as it should be.

"Other direction" mentioned by Ross relates to a possible additional airframe product utilizing some of our current technology. The core of our business is kit airframe production, for airframes suited to engine choices such as the M-14 radial and the LS V8. I like both of these engines, for different reasons, and interest from potential kit purchasers is equally split. I do think that reintroduction of the Formula GT, with LS V8 power, would tip the numbers in favor of the V8. (Did I mention I am trying to roll back my work load?...)

Jeff
 

Toobuilder

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Glad to hear it Jeff. I am interested in getting a look at the P85 one of these days - particularly in comparison to my Rocket as a possible (eventual) replacement candidate. Glad the focus will remain on the V-8 option.
 

Jeffd

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Flew the new stack exhaust system for the first time on the P85 today - it has been in the works for a while. Wanted to compare it to the 2-into-1 down-pipe system. In the process of installing the stacks, several reasons came to mind as to why this might be the preferred system. I'll follow up after getting more flight time .

IMG_4868 web.jpg

Video gives an idea of the sound, although there is some echo off of the metal hangars:

 
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Toobuilder

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Jeff, aside from aesthetics and weight, why would a stack system be desirable? With a NA engine, there is so much power to be gained from correct exhaust scavenging it would be hard for me to turn my back on.
 

Jeffd

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Jeff, aside from aesthetics and weight, why would a stack system be desirable? With a NA engine, there is so much power to be gained from correct exhaust scavenging it would be hard for me to turn my back on.

I'll need some more flight time, refinement of general cooling airflow over the engine and refinement of Meredith duct airflow management before I can answer your question. At the end of the day though, I suspect that stacks will be the better choice. We'll see...

Jeff
 

TXFlyGuy

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This is interesting. We just had our LS376/480 put on a dyno with longtube headers. Note that GM only claims 480 hp for this engine.

525 hp was recorded at 6,000 rpm
430 hp @ 4500 rpm.

The dyno shop said to expect up to a 9% power loss when installing the P-51 Mustang style short stack headers. I have scoured the internet (YouTube / Hot Rod Magazine / Car Forums) to find that the real drop off in performance is in the neighborhood of 4% to 6%.

Did you dyno your engine? What were the numbers? How much (if any) drop do you expect with the short stack headers?

P1020702.jpg P1020703.jpg
 

Jeffd

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Location
Overland Park, Kansas USA
Dyno pulls for car magazines and customers are typically brief affairs, lasting 30 seconds or less, and are designed to produce the biggest numbers. Intakes are usually not obstructed with ducting/filters, and optimized long-tube header systems are the norm. In addition, higher "magazine" HP numbers are achieved via application of an older, less stringent standard for HP measurement, as opposed to what automakers currently use.

In an actual car or aircraft you will see "installed HP", representing actual intake and exhaust system hardware. The engine installed in the P85 was dyno'ed and produced typical/expected numbers for this engine build. Once the engine is installed in the plane and operated with service life in mind, all that matters is the true airspeed number - the airframe is a good real world dyno, and speed changes due to engine mods will say a lot about horsepower.

I can easily believe that a stack exhaust system could cost 5% HP compared to long tube headers. The only way to really know would be to dyno the installed configuration (as some have done), but having said that, I have yet to see a dyno cell that can simulate the 300 mph breeze seen by the intake and exhaust systems in the plane.

Jeff
 
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TXFlyGuy

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Our initial dyno run was to establish a base line for what the LS3 with the GM Hot Cam would do. We should have numbers for the short stack headers soon. All of this is being performed at a school in Houston, Texas.
Certainly they would use current accepted criteria for evaluation of horsepower and torque.

For fuel burn, .5 lbs/hr/hp seems high. That would put us at 19 gph at 10,000'. We have an electronic fuel injection system, controlled by an aftermarket ECU (New Zealand).
 

TXFlyGuy

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Flew the new stack exhaust system for the first time on the P85 today - it has been in the works for a while. Wanted to compare it to the 2-into-1 down-pipe system. In the process of installing the stacks, several reasons came to mind as to why this might be the preferred system. I'll follow up after getting more flight time .

View attachment 66607

Video gives an idea of the sound, although there is some echo off of the metal hangars:

[video=youtube;C2qVw1A6dt8]https://www.youtube.com/watch?v=C2qVw1A6dt8&feature=youtu.be[/video]
I want to see a night video, complete with flames belching out of those stacks!
 
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Jeffd

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Joined
Dec 15, 2011
Messages
115
Location
Overland Park, Kansas USA
Our initial dyno run was to establish a base line for what the LS3 with the GM Hot Cam would do. We should have numbers for the short stack headers soon. All of this is being performed at a school in Houston, Texas.
Certainly they would use current accepted criteria for evaluation of horsepower and torque.

For fuel burn, .5 lbs/hr/hp seems high. That would put us at 19 gph at 10,000'. We have an electronic fuel injection system, controlled by an aftermarket ECU (New Zealand).
So, you are saying your engine burns .5 lb/hp/hr?
 
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