I'm hoping Bruce Lockwood might answer this since he has been posting here a lot lately. It seems like boil off cooling is going to be a big deal in the next few years, and you said in a previous post that you were heavily involved in the design of the system on Stileto. Is there a particular reason why boil off cooling wasn't tried on Dago Red? Or were you guys fast enough that you just didn't need to try it?
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Re: Dago Red Question
Rampman, the short answer is that we felt we were fast enough. But... you guys/gals general like more information so I'll expand on that a little.
As Alan Preston used to tell me "Plan the fight then fight the plan". So the first thing on the agenda for me back in 1994 when David Price said lets go and win Reno, was to do a little research into why a competitive Unlimited Gold racer would win/lose a race. To fully understand this, lets look at the 4 basic elements it takes to win the Gold (and.... by the way this still applies today).
1. A Fast airplane and Race pilot..... with the following caveats:
*You have to be able to clearly see the course or you"ll cut pylons
* Systems management needs to be simple (Auto spray bar etc)
* Easy to decipher instruments with critical instruments at the upper
left quadrant of the instrument panel, telemetry
* All race related switches in one spot; IE upper right of panel
* Aircraft Flight quality on the course; IE big propellers/lots of power
make for poor handling and you cant get in tight on the pylons or
close in formation. Ask Matt how Rare Bear flew with the 3 blade,
its faster on the straight line but slower on the course.
2. The ability to make lots of thrust (a combination of engine HP, prop
efficiency, and exhaust thrust) This is limited by the engines
structural strength, fuel performance number, induction temp and
RPM/ MP.
3. Systems reliability IE. Pumps, ADI regulators, check valves, switches,
wiring, generator/battery, and the cooling system (coolant, oil,
induction).
4. LUCK (Made by detailed preparation..... or the old fashioned way
by humbling asking for it).
A trend revealed that most often races WERE NOT lost by a catastrophic engine failure on its own as in "the engine just wasn't strong enough" but in a failure of systems which broke the engine: IE spray bar pump fails, engine over heats: ADI systems malfunction engine detonates breaks rods/pistons: carburetor malfunctions and burns pistons: Prop governor fails and over-speeds engine. Ignition system/ignition coils, spark plugs, engine down on power: Electrical systems malfunctions and pumps don't pump at their designed pressures (Low voltage). Pilot forgets to turn systems ON prior to the race start or to monitor/adjust systems during the race.
Add to that is the surprising number Golds that have been lost due to pylon cuts. Its faster to go tighter...... but you pay the penalty.
We felt that our best shot for winning was not to reinvent the wheel, with a boiler system so to speak, but to address systems reliability issues. If we could run all week without a systems failure, which invariable hurts the engine and limits the power available for Sunday, we could be at 100% when we needed and be able to run down or break the competition. So a huge amount of our budget and time was spent on items 1 and 3 from above. The engine was handled by Mystery Air and luck..... well you know how she can be.
A short example of this would be the 4 different instrument panel/switch layouts that were tried until we found the one that proved best. Another was changing from the traditional 100 AMP alternator to a special one off 300 AMP generator that Rich from RB AERO custom built. But every item was methodically addressed.
Now if you apply that same mentality to a boiler system.......who knows how fast you can go. But remember, its still called racing and if you don't believe that, look at how many times the number 1 qualifier for the Indy 500 is not the one drinking the coveted glass of milk in victory lane.
Hope that answers some questions, Bruce -
Re: Dago Red Question
Well addressed Bruce. It was put in laymans terms that even I understood it. I was on the Saturn missile at the Cape & the general public didn't grasp the thousands of things that had to happen in a short time to get a successful launch. Everything had to come together in sequence. Plane & pilot have to become one while racing to finish first. My 2Cents.
Lockheed BobComment
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Re: Dago Red Question
Very good and easily understood reply Bruce. Being a "gearhead" with many years experience in motorsports and racing, and twenty-five+ years racing at Reno, I would like to add some comments specific to boil-off cooling systems since, of late, "boil-off" has become quite a buzzword among air race fans and on this board
Several years ago I recall an Unlimited pilot, perhaps Lyle Shelton, stating that management of consumable fluids was the most critical part of operating the aircraft. Other than fuel, ADI and spray bar fluids being the most common; mismanage either and your chances of winning are pretty much over, or worse.
While a boil-off system is an efficient low-drag method of removing heat from an engine, it is limited by the amount of boil-off fluid available. In a boil-off system, hot engine fluid, whether it be engine oil or liquid engine coolant, is circulated through a heat exchanger (radiator) immersed in a tank (boiler) containing the boil-off fluid. That fluid absorbs heat from the hot engine fluid eventually raising the temperature of the boil-off fluid to its' boiling point, and the resulting steam (vaporized boil-off fluid) is vented overboard. Additional boil-off fluid can be added (pumped into the boiler) but eventually all of the boil-off fluid will be vaporized (consumed) and the engine fluid will overheat. The quantity of boil-off fluid available is limited by space and weight.
I cannot speak knowledgeably as to how much boil-off fluid is typically consumed in a race, but it is one more critical fluid that must be managed.
As a system, boil-off adds weight and complexity to an aircraft that teams work very hard to make light and simple. If the benefits gained from drag reduction exceed the losses of added weight and complexity, then the boil-off is worth it, but once the fluid is gone...it's gone.
Simply put, boil-off is not the panacea of all things that make airplanes go fast.Last edited by Skyracer; 10-24-2009, 09:15 PM.Comment
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Re: Dago Red Question
Bruce,
Are (were) there any structural fuselage mods done to Dago strictly for strength? I have seen a photo floating around that shows a relatively stock Mustang that was showing a lot more "oil canning" that I have ever seen on a Mustang. None of the race bread 'stangs like Dago or Strega have any visible signs of that happening.Comment
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Re: Dago Red Question
Bruce, thank you for your quick, and as usual, well explained and detailed response. The technical info coming across this board lately has been amazing. It's going to be interesting to see how these new boil off systems pan out for the teams trying them.
When Dago Red reapeared in the mid 90s it was shocking to see how well it was prepared and how fast it had become. By your posts it's obvious how much thought and hard work went into that effort.Comment
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Re: Dago Red Question
[QUOTE=bruce lockwood;75811]
A trend revealed that most often races WERE NOT lost by a catastrophic engine failure on its own as in "the engine just wasn't strong enough" but in a failure of systems which broke the engine: IE spray bar pump fails, engine over heats: ADI systems malfunction engine detonates breaks rods/pistons: carburetor malfunctions and burns pistons: Prop governor fails and over-speeds engine. Ignition system/ignition coils, spark plugs, engine down on power: Electrical systems malfunctions and pumps don't pump at their designed pressures (Low voltage). Pilot forgets to turn systems ON prior to the race start or to monitor/adjust systems during the race.
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Bruce, following this reasoning and awesome explanation, can I deduce that in the years ago the v12s (generally speaking), were suffering from the systems that assist the engine? and not so much from the engine itself?. And going on, that 2009 can be considered as that the systems were better handled?.
As any research and development, it can demand many bad moments until you get all the eggs together.
Thank you a lot for your assistance.
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Re: Dago Red Question
[QUOTE=taglialavore;75817]Great write-up, Bruce. Very insightful.Originally posted by bruce lockwood View PostA trend revealed that most often races WERE NOT lost by a catastrophic engine failure on its own as in "the engine just wasn't strong enough" but in a failure of systems which broke the engine: IE spray bar pump fails, engine over heats: ADI systems malfunction engine detonates breaks rods/pistons: carburetor malfunctions and burns pistons: Prop governor fails and over-speeds engine. Ignition system/ignition coils, spark plugs, engine down on power: Electrical systems malfunctions and pumps don't pump at their designed pressures (Low voltage). Pilot forgets to turn systems ON prior to the race start or to monitor/adjust systems during the race.
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Bruce, following this reasoning and awesome explanation, can I deduce that in the years ago the v12s (generally speaking), were suffering from the systems that assist the engine? and not so much from the engine itself?. And going on, that 2009 can be considered as that the systems were better handled?.
As any research and development, it can demand many bad moments until you get all the eggs together.
Thank you a lot for your assistance.
Regarding the systems, even the very best engine build will fail if any ONE of the systems fails to work properly, inline or radial. This is something people fail to realize in large part. The assumption is that a racing engine failure is consistently the fault of the builder, but as Bruce points out, that's typically not the case. It can literally be the demise of a $10 part which can cause a catastrophic engine failure, and sometimes all the preparation in the world can't prevent that. I believe that's where the "luck" factor comes into play.
SALast edited by Smee Again; 10-25-2009, 09:10 AM.Comment
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Re: Dago Red Question
Wow, more good questions and observations. I'll try to answer them in order.
SKYRACER, with regards to the boiler, I gave some fairly in-depth info about how the system work in another post.....2/3weeks ago.
RACE 5, good question and surprisingly the answer is no. The only strengthening mods, if you want to call them that would be to make sure you have "late series" aluminum trim tabs and not the older style phenolic. The other upgrade would be going to a solid engine mounts in lue of the rubber mounts as there is a much larger torque reaction being imparted into the motor mount frame.
Hopefully I remember the formula right Ha! but here goes.
Stock Merlin 1500 Hp apx @3000rpm (1500 x 5250 /3000= 2625 ft lbs of torque) now remember that the engine has a gearbox that slows down the prop/increases the torque... so take that ratio .479 and divide it into
2625/.479=5480 ft lb of torque on the motor mount.
Now take the race motor: 3800Hp @ 3400rpm (3800 x 5250/3400=5867 ft lb of torque. Divide that by the gear box ratio of .42 (5867/.42= 13969 ft lbs of torque. So Stock Engine puts = 5,867 ft lbs of torque on the mounts and the Race Engine puts 13,969 ft lbs of torque
So you can see that we are coping with 2 1/2 times the load on the motor mount... those poor little rubber doughnut get smashed flat and allow the engine to twist under the cowling. this is hard on the coolant/oil tubes, engine controls, generator/after-coolant pump as they can rub directly on the mount
TAGLIALAVORE, yes, generally the teams in the early days didn't have the money to go through all the systems. They spent most of the money on getting the engine ready and maybe fresh paint. This is a deeper subject than I have time to answer for now so remind me sometime this winter and we will revisit this.
SMEE AGAIN, well put. Look at Dan Martin a year or so ago when a $10 check valve allowed the ADI system to drop pressure and instantly Sparrow's/Dan's very potent/reliable race motor was parked on the ramp. I was sad to see that happen.
Cheers BruceComment
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Re: Dago Red Question
Actually, I hve a picture of Dago Red the first year it was raced. My buddy was out on pylon1 and took the pic on Sat. heat race. He showed me the pic a couple of weeks after the race. The rear fuselage was "oil-canned" above the scoop. I gave Ron Hevle a copy of the pic. the next year at Reno and he was very suprised to see the fuselaage wrinkles.Originally posted by Race5 View PostComment
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, I missed it (my bad).
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