Dago Red propeller / Qualifying run

[Griffon58]

On the subject of the 500 mph lap thread, the spectacular photos of Dago red were very revealing regarding propeller pitch. The blade angle seemed extraordinary, as I did not think that they would almost appear feathered! What is the pich angle of those blades at speed?

Second, why does the 500 mph qualifying lap matter at all? It seems to me that the stress of this is what flattenned Tiger's chances last year, and has weakened many otherwise healthy engines for little gain. If Dago qualifies at 440 this year, and simply bumps up she will arrive in the gold with a healthy powerplant that has been tuned up all week. With the new Brown Fury possibility, she may need an engine that completes all the laps on Sunday. Why break on Tuesday?

Last and a non sequiter, but the post on the unlimited Hydros was neat, and there were boats running this weekend in Seattle. ( Restored thunderboats) Regardless of how neat they are, and I was thrilled to see the Allison win, is this dangerous for air racing? Many people today know that boat racing destroys engines at a faster rate than air racing, and these are finite resources. Parts of the Strega motor were literally one of a kind due to the carelessness of the past. Now with a resurgence of boat racing demand, restoration of classic raceboats demanding more engines, (less threatening) and tractor pulls in Europe demanding Griffons and Allisons too, will prices and parts dissappear ? The odds of constructing new V-12's in this size are remote and it is estimated there are 3,000 of these engines remaining worldwide. What do you think?

[Unregistered]

As for Dago's qualifying lap, it's really NOT a matter of shooting for any records with the team, they simply run a predetermined power setting and let the chips fall where they may. This is the same power setting the Dago team has run since the installation of the first Thorn Mouse back in 1996, when David Price qualified at 490.8 MPH, and believe me, it's really quite conservative given the power that motor is capable of. So as for Dago, burning the fuse early is NOT part of their plan, but if their normal power setting gets them the 500 MPH lap, great, if not, that's cool too. Kerch has often told me all he really wants is a top 5 position in qualifications.

And yes, those pics of Dago's nearly feathered prop are impressive to say the least. Just a testament to the awesome power the Mouse Merlin is pumping out even at that realtively conservative power setting. I can't wait for Reno 2003!

The Phantom Samurai

[hattend]

Griffon58,

Do you know the answer to the question "Are the hydros going back to piston power"?

Are the turbines sucking up too much water or what? I just can't see going backwards.

And no, I'm not saying I don't love the sound of piston power... The Wright R3350 sounds awesome!!!

Don

[Griffon58]

Return to Pistons

The driver of the Allison 1710 boat on his post race interview stated that he hoped that more teams would enter or return to competition based on the fact that though lower tech, pistons were the ideal powerplant for those on a budget. He seemed to infer that Turbines were far more costly than piston power, and that secondly, there were more in the wings.

After watching a poker run in the Hudson last year, I was introduced to the Skater brand of boats in brutal fashion. Looking over the Cigarettes and Scarabs, it was a surprise to see a turbine Skater boat, (a Catamaran) in the dock with a fairly plain paintjob. There is also a dual Big Block one in Lake Mead...
Well that darn turbine Skater went so fast it outran the Helicopter! No piston boat had done that! At that point I was hooked on turbine power, however, you must get Jet A to the dock to run. Only a threat to the availability of piston fuel at the boat dock will bring turbines to widespread use, so they are a rarity except in unlimited hydros and the US Navy ships. Pistons therefore have a very nostalgic pull for the boat racers, and due to PR driving sponsorship, could make inroads to the sport for other piston teams.

[Unregistered]

Re: Dago Red propeller / Qualifying run

Originally posted by Griffon58
On the subject of the 500 mph lap thread, the spectacular photos of Dago red were very revealing regarding propeller pitch. The blade angle seemed extraordinary, as I did not think that they would almost appear feathered! What is the pich angle of those blades at speed?

I've made that comment before as well- blades that look feathered are the mark of a competitive racer with a serious head of speed on! The pitch of the blades is determined by the RPM setting, the throttle setting, and the airspeed. The blades will move toward "feathered" with increasing airspeed, with DEcreasing RPM setting, and with increasing throttle (manifold pressure). At high speed, the prop needs a lot of pitch to "bite" the air (maintain the right angle of attack relative to the airstream) and the engine has to produce a ton of torque to spin the blade that way. Thats what it takes to go fast.

Another airplane that always shows this aggressive propellor pitch on the course is the mighty Dreadnought, but instead of using ungodly manifold pressures, she does it with an ungodly number of cylinders :-)

Steve L.

PS- the photos of Mike Brown's F7F from "rookie shool" also show an agressive prop pitch, but its obviously not moving as fast as Dago. In this case, its an example of a stock plane being flown at the upper end of its speed capability. Its stock props can't absorb as much power as can the prop on Dago, Dreadnought, or Rare Bear, so they "feather" at lower power output and speed.

PPS- Doc, have fun laughing at my naive understanding of all this any time. :-)