Before it was Rare Bear

[BellCobraIV]

Re: Before it was Rare Bear

I'm not sure that the exhaust system in that photo is the version that was installed during the Bearcats glory days but I'd be happy to be corrected. The good exhaust was a nightmare to work on. I can recall questioning why anyone would put together a puzzle that cantankerous and being told it was "tuned", the pipe from each cylinder would join the pipe from a cylinder preceding in the timing order to help exhaust gas scavenging and contribute a small amount of thrust. The exhaust exits also worked as a venturi (exhaust augmenter), the exhaust actually helped to cool the engine (unless part of it failed) by motivating the air under the pressure cowl to exit. That system had gone through so many heat cycles that it was almost beyond repair and anytime it was disassembled it was a nightmare to reassemble because nothing fit, nothing would line up and you'd have to start taking it apart again. With all of that said, it should've been replicated not scrapped.

Lyle had flown on TWA trips with George Byard's brother. That is the initial way that Lyle got to meet George and start the most beneficial support that the Bearcat racing project would ever have. George Byard owned Aircraft Cylinder and Turbine a major player in the radial engine business in Southern California. The first rodent infested, trash covered engine that the team received came from AC&T and George Byard. They didn't have any exhaust, not did anyone else have exhaust for an R-3350 in a Bearcat QEC, however AC&T did have several crates of exhaust that had been removed from R-3350 engines for Constellation and DC-7 aircraft. Lyle bought a complete engine mount and exhaust from a Skyraider, those parts didn't even think about fitting on the Bearcat!

So one of the crates was brought down to the Compton hangar F8 (the first hangar Lyle had) and was used by Cliff Putnam to build the first somewhat crude but effective 2 into 1 exhaust set on the Bearcat. Over the years that exhaust that Cliff had built was maintained on ocassion as it would break often out of those parts that were in the crates of exhaust.

One of the things that Dave Cornell brought to the table was his history in motorcycle racing. Dave as he became more involved in the Bearcat decided that a complete revamping of the exhaust system was going to be necessary. Cliff's original system while designed to be two cylinders down to one exhaust pipe which was good didn't take into account pairing of the cylinders by firing order in order to maximize the scavenging effect of the cylinders paired to achieve two to one exhaust pipes. Dave went back to AC&T who still had crates of exhaust pipes for the Turbo Compound engines picked up more pipes and started over. He was having Rich Donahue take the pipes from the crates and by cutting and fitting the Dave and Rich fitted the pipes in the pairing of cylinders to provide the optimum effect of scavenging.

The next and most secret part was to optimize the back pressure to exhaust outlet velocity by machining rings that were shaped and sized in a manner that would make the best use of the pressure cowl design that Dave and Bill Prewitt were installing based on the DC-7 cowling. Bill was an excellent sheet metal fabricator and was able to bring to reality the design Dave envisioned.

The spinner off a Bristol Beverley was adapted to the four blade propeller and we were able to close down the gap between the spinner outside diameter and the cowlings inside diameter to a ridiculously small looking dimension. Without proper exhaust augmentation the engine simply would not have had enough air going through the cowling to cool the engine. A metal plate system was developed to increase the venturi effect between the higher velocity exhaust gasses and the slower cooling air. Ultimately flight tests showed that at speed the "flat plate" area between the gap of the cowling and spinner was negated to near net zero. The spinner afterbody that was fabricated by Prewitt under Cornell's direction shaped the airflow to get the maximum use of the air going through the cowling. To finish the package the baffles were installed using silicone sealer to control the airflow better. High temperature rubber pieces were installed to manage the airflow at the cylinder base gaps.

Torque meter readings showed that the augmented improved exhaust system was good for close to 300 horsepower, the engine cylinder head temperature was reduced and flight test numbers showed a significant speed increase due to the reduced drag.

So a really good system started by Cliff Putnam was perfected and included in a package of air/engine management thought up by Dave Cornell brought to life by the metal shaping magic of Bill Prewitt. Rich Donahue gets credit for training the exhaust pipes to fit as needed. Lief was correct, working on the exhaust was a Bearcat kinda deal.

[knot4u]

Re: Before it was Rare Bear

I can recall a long ago conversation in a mini van amongst friends, I was still a fairly young man and I pondered whether a female named after her mother should be called Junior? It quickly turned into an interrogation regarding my private activities, but I've still never gotten an answer to that question. If someone names their daughter after the mother can that child be considered a Junior?

[wingman]

Re: Before it was Rare Bear

Thank you very much for the detailed post, knot4u. I'm not an engineer, or a mechanic, so can't evaluate in detail much of the tech side of this, but what you are saying makes sense and could well explain some of what I saw over the last few years of Rare Bear racing efforts. It would be interesting to find out whether the developed system you describe does date from the beginning or from a later point in Bear history. Some of it sounds a lot like Dave Cornell thinking, but when I think of the really remarkable thinking that went in early on, like thrust line changes and that remarkable canopy I can only marvel at what these guys were doing right from the beginning.

Stuff like this makes me glad not to be a mechanic. Thank you again for the post.

Another Pete Behenna photograph:

[knot4u]

Re: Before it was Rare Bear

Another thing I'm curious about is this exhaust system, which is apparently quite unique. There's been a lot of talk here over the years that this 2 into 1 setup was worth 200-300 horsepower, and that one of the huge mistakes by the Texans was to replace it with a more conventional system. Why did this work so well, and who came up with the design?

Pete Behenna photo...

I'm not sure that the exhaust system in that photo is the version that was installed during the Bearcats glory days but I'd be happy to be corrected. The good exhaust was a nightmare to work on. I can recall questioning why anyone would put together a puzzle that cantankerous and being told it was "tuned", the pipe from each cylinder would join the pipe from a cylinder preceding in the timing order to help exhaust gas scavenging and contribute a small amount of thrust. The exhaust exits also worked as a venturi (exhaust augmenter), the exhaust actually helped to cool the engine (unless part of it failed) by motivating the air under the pressure cowl to exit. That system had gone through so many heat cycles that it was almost beyond repair and anytime it was disassembled it was a nightmare to reassemble because nothing fit, nothing would line up and you'd have to start taking it apart again. With all of that said, it should've been replicated not scrapped.

[wingman]

Re: Before it was Rare Bear

Another thing I'm curious about is this exhaust system, which is apparently quite unique. There's been a lot of talk here over the years that this 2 into 1 setup was worth 200-300 horsepower, and that one of the huge mistakes by the Texans was to replace it with a more conventional system. Why did this work so well, and who came up with the design?

Pete Behenna photo...

[Racer 18]

Re: Before it was Rare Bear

Just additional information on the crew in 1969;
Top left to right: Bill Kientz (TWA PIlot, electrical expert), Bill Hickle (China Lake/later Flight Systems Mojave), Lyle Shelton (TWA Pilot/Navy Reserve, Expert Air Racer), Cliff Putnam (TWA Pilot, Mechanical Expert & Crew Chief), Harry Smith (American Airlines A&P).

Bottom left to right. Austin Cranston (Navy Navy Chief, Los Alamitos), Randy Difani (grunt), Dennis Buehn (Navy Crew Chief), George Williamson (Navy Los Alamitos), Pete Behena (American Airlines A&P, Photographer).


Randy, since you are on here and may have a better memory of the dates, Neal was inquiring about the timeline of the events as they unfolded. I have been going through what archives we have as I can get to them and have not found Lyle's yellow 11x14 pages from 1969 yet. We have his Daytimers sorted out but they only start in 1970 from what I've been able to find.

This thread has uncovered a lot of information and I have to dig to get at it now. My Mom is now 90 years old and can't remember what car we are in anymore, let alone what the white and purple airplane is in the pictures on the wall.

"John -- what was the timeline of all this? When did Lyle move the kit into the hangar? When was the fuselage more or less complete? When did Putnam get his hands on the engine and when was it actually hung on the airplane?

Neal"

For reference.

John,

Unfortunately, I do not know anything about Lyle's timeline for procuring, transporting, etc. of Able Cat. I arrived on the scene approximately late spring/early summer 1969. Saw a funny airplane (first thought it was P-51) on it's gear, sans firewall forward, driving by Compton. I stopped in and this guy was cleaning/stripping a part on the ramp. I asked if he knew who owed it and he said I do...I asked if he could use help and he said yes. I didn't know anything about working on aircraft...but the rest is an amazing exciting history for me. Many many volunteers helped get Able Cat to Reno in 1969. However, the technical/mechanical spark plug/leader of the repair effort was Cliff Putnam. Also, he was a super nice guy along with all the people I worked with. Of course Lyle was traveling the country gathering up the needed parts, etc. to get Able Cat flying.

Randy

[Lon Moer]

Re: Before it was Rare Bear

Found another one......

[BellCobraIV]

Re: Before it was Rare Bear

My recollection of Reno 1969 Able Cat crew pictured as follows:

Bottom left to right. George (Navy Los Alamitos)?, Randy Difani (grunt), Dennis Buehn (Navy Crew Chief), George (Navy Los Alamitos)?, Pete Behena (AA A&P, Photographer).

Top left to right: Bill Kientz (TWA PIlot, electrical expert), Bill Hickle (China Lake?), Lyle Shelton (TWA Pilot/Navy Reserve, Expert Air Racer), Cliff Putnam (TWA Pilot, Mechanical Expert & Crew Chief), Harry Smith (AA A&P).

Most repair/restoration work accomplished Hangar F8 Compton, CA. Towed to Santa Ana, CA. First flight to Chino, CA, where yellow zinc chromate painted, approx. one week prior to Reno. Took 5th place 1969 Reno Gold Unlimited. Great fun and extraordinary experience. We stayed at the Mapes Hotel, downtown Reno. Possibly John can add details.

Randy Difani (T6 Racer #18 "Thunderbolt" ret.)

PS Recall Lyle returning from reserve duty overflying Compton in an A4 Skyhawk, with drop tanks, prior to landing at Los Alamitos.

Just additional information on the crew in 1969;
Top left to right: Bill Kientz (TWA PIlot, electrical expert), Bill Hickle (China Lake/later Flight Systems Mojave), Lyle Shelton (TWA Pilot/Navy Reserve, Expert Air Racer), Cliff Putnam (TWA Pilot, Mechanical Expert & Crew Chief), Harry Smith (American Airlines A&P).

Bottom left to right. Austin Cranston (Navy Navy Chief, Los Alamitos), Randy Difani (grunt), Dennis Buehn (Navy Crew Chief), George Williamson (Navy Los Alamitos), Pete Behena (American Airlines A&P, Photographer).


Randy, since you are on here and may have a better memory of the dates, Neal was inquiring about the timeline of the events as they unfolded. I have been going through what archives we have as I can get to them and have not found Lyle's yellow 11x14 pages from 1969 yet. We have his Daytimers sorted out but they only start in 1970 from what I've been able to find.

This thread has uncovered a lot of information and I have to dig to get at it now. My Mom is now 90 years old and can't remember what car we are in anymore, let alone what the white and purple airplane is in the pictures on the wall.

"John -- what was the timeline of all this? When did Lyle move the kit into the hangar? When was the fuselage more or less complete? When did Putnam get his hands on the engine and when was it actually hung on the airplane?

Neal"

For reference.

[Racer 18]

Re: Before it was Rare Bear

Photo via Bill Kientz
" Early 70?s. In 1974 he would become Lyle Shelton?s crew chief on Rare Bear. "

My recollection of Reno 1969 Able Cat crew pictured as follows:

Bottom left to right. George (Navy Los Alamitos)?, Randy Difani (grunt), Dennis Buehn (Navy Crew Chief), George (Navy Los Alamitos)?, Pete Behena (AA A&P, Photographer).

Top left to right: Bill Kientz (TWA PIlot, electrical expert), Bill Hickle (China Lake?), Lyle Shelton (TWA Pilot/Navy Reserve, Expert Air Racer), Cliff Putnam (TWA Pilot, Mechanical Expert & Crew Chief), Harry Smith (AA A&P).

Most repair/restoration work accomplished Hangar F8 Compton, CA. Towed to Santa Ana, CA. First flight to Chino, CA, where yellow zinc chromate painted, approx. one week prior to Reno. Took 5th place 1969 Reno Gold Unlimited. Great fun and extraordinary experience. We stayed at the Mapes Hotel, downtown Reno. Possibly John can add details.

Randy Difani (T6 Racer #18 "Thunderbolt" ret.)

PS Recall Lyle returning from reserve duty overflying Compton in an A4 Skyhawk, with drop tanks, prior to landing at Los Alamitos.

[Lon Moer]

Re: Before it was Rare Bear

Photo via Bill Kientz
" Early 70?s. In 1974 he would become Lyle Shelton?s crew chief on Rare Bear. "

[AAFO_WSagar]

Re: Before it was Rare Bear

Yea... this ain't Facebook... LOL

Love it you guys!

One of the things I've missed here is the exchange of some of you... excuse me, "old timers"

Used to be a lot of banter among crew/pilot.. I think it all sort of felt "inside" and sheltered here (ads but none shoved up your keyster... that I'm aware of!) but it still came off as pretty private..

So anyway, you two were around BEFORE IT WAS RARE BEAR so your cross talk is extremely entertaining..

Neal, John I know how memories fade, these chats run some mental dental floss between those forgotten portions...

Again, keep it up please!

[wingman]

Re: Before it was Rare Bear

I told you my memories of those days are a bit jumbled, and clearly not all quite in order. I guess I must have been listening to Stairway in Mill Valley and not in Ann Arbor -- 1973 and not 1968. It does all seem so long ago. I still don't remember that song.

I agree -- back to Air Racing.

Neal

[BellCobraIV]

Re: Before it was Rare Bear

I just looked up That Evermore Zeppelin song, and I can see how a person could get sucked in. I don't remember much Zeppelin after Stairway to Heaven. When the Evermore song apparently happened I was otherwise engaged -- chasing nurses, avoiding personnel sergeants carrying orders to faroff places, and wondering about the young guys dying of strange tropical diseases on my watch in the hospital. I don't remember much music or music news during that time. Of course like many Baby Boomers there are other reasons why I don't remember a lot of that time, but better not to go there. The nurses sure were fun, though.

That's my excuse for such ignorance, anyway. I forget that a bunch of you guys are 10 or 15 years younger than I am.

Neal

Neal, Neal, Neal, how ironic you should say that after "Stairway to Heaven" you don't remember much Led Zeppelin, on the actually not named Led Zeppelin IV the fourth track is "Stairway to Heaven" following the third track which is the "Battle of Evermore." The Battle of Evermore was based on J.R.R. Tolkens "Lord of the Rings". Let me tell you if you had to keep up with my daughter and Brad playing music trivia you'd study as well. My daughter when she was twelve shredded a guy once with the facts when he said Yoko broke up the Beatles. Nope afraid not dude, read better history. (Not my comment to you
, That was my comment to the 40+ year old guy that she shredded.)

Now back to Air Racing....I promise.

[AAFO_WSagar]

Re: Before it was Rare Bear

Be strong grashopper, you can resist the force of the farce....

Truly should have worded that...

Be strong Obi-Wan, you can resist the force of the farce....

[wingman]

Re: Before it was Rare Bear

I just looked up That Evermore Zeppelin song, and I can see how a person could get sucked in. I don't remember much Zeppelin after Stairway to Heaven. When the Evermore song apparently happened I was otherwise engaged -- chasing nurses, avoiding personnel sergeants carrying orders to faroff places, and wondering about the young guys dying of strange tropical diseases on my watch in the hospital. I don't remember much music or music news during that time. Of course like many Baby Boomers there are other reasons why I don't remember a lot of that time, but better not to go there. The nurses sure were fun, though.

That's my excuse for such ignorance, anyway. I forget that a bunch of you guys are 10 or 15 years younger than I am.

Neal