Warbird Information Exchange

I am looking for some Reduced power takeoff charts for the DC-3 with 1830 engines.

not a good idea. look at Precision Engines website and see why...

Dont think you will find any, we had to use rated power on all checkrides cause we could not show performance without. Dont recommend reduce power anyway any more, we found that it did not really change anything in the long run. If you make TBO or not seemed at times to just be a roll of the dice. We had preoil pumps and good ops procedures, didnt change much!
KABOOM! would still happen occasionally on low timers and high time engines. We had a TBO on our certificate of 1200 hours early on and i had a main bearing go at 1199.5!! so whatayadoo???

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"Never in the field of human conflict was so much owed by so many to so few"

There is a service letter out by P&W re this topic and it says that it is a big no no to use less than the rated power for takeoff. Turbine engines are very different and may under certain applications use derated power for takeoff...

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..defeat is never an option!

With the R-3350 Turbo-Compound engines in the DC-7 and P2V, we have to use reduced power,but that is a de-rating to prevent detonation that could result from the use of lower than specified grade fuel.These engines were designed to use 115/145.I have a P2V-5F flight manual from 1961 that has power setting to use when only 100/130 is available.These are the same settings that are in use today for these engines.The horsepower available for max power on the DC-7 works out to 2880 hp for 100/130 vs. 3250 hp with 115/145.However,we still run very close to the max 100/130 power manifold pressure/bmep limits for take-off using 100LL,even empty for reasons mentioned in the link in a previous post above.

Does anyone know when 115/145 fuel came fully into use? My impression was it was only about the last year of the war. I don't know much about radials, but we had a discussion of Merlin power and longevity in the seminar. John Baugh got over a 1000 hours on his P-51 engine, and he said every takeoff was at a full 61 inches. I believe the Crazy Horse guys use 55 inches for takeoff, Jack Roush was advising less, I think 50 inches. I don't know if there is an absolute either way. Normal takeoff power in Merlin Spitfire is 7 lbs boost or 44 inches. At full combat weights they could use 12 lbs or 54".

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Bill Greenwood
Spitfire N308WK

I have the same issue with the ADs 3350. The military used 60 inches and 115/145 gas. Because of detonation I use 48 inches with a five min limit on 100LL.
No need for 60 inches in the airshow world, I took off from the Cape Girardeau Airshow at 96F, with 3 people, 450 pounds of gear, 4100 pounds of gas, 12 rockets and it was a non factor. I was a little worried though because I was within 6000lbs of max gross weight.

Bill Greenwood wrote:


What was that, like 4500lbs gross weight or so?

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Eric

"I spent most of my money on alcohol, women and skyraiders....and the rest of it I just wasted."

The last time we flew FIFI we used reduced power, by the time I got the throttles and power lined up we were airborne. I believe we were flying at about 80,000 lbs., 2800 rpm, 40 inches MAP, and used about 4,000 feet of runway. No sweat...

C-54 T/o at around 55K 42"MAP 2550 RPM as opposed to 50" and 2700 RPM.

1st engine change was at 1700HRS

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Kevin Kearney
Vice President
Berlin Airlift Historical Foundation


C-54D "Spirit of Freedom" 43-17228
C-97 "Angel of Deliverance" 52-2718 (painted as YC-97A 45-59595)
C-54E/R5D-4 "Spirit of Freedom" 44-9144 BuNo 90414 (wfu April/2020)
http://www.spiritoffreedom.org

Grasshopper, you are traveling a winding road with many forks. You seek an answer that does not exist. Only controversy and anguish will you find. The true meaning of life is easier to determine than that which you now seek.

If Bill ever needs a way home you can give him a tow

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Don't touch my junk!!

Now that was funny. I almost spit coffee on my computer.

The last KC-97L flight manuals had charts for using reduced power in the event you had to use 100/130 fuel instead of 115/145. Basically you used about five inches less MAP (55" verses 60"). It reduced your BHP from 3,500 to about 3,100 BHP. The manual also had takeoff distance charts adjusted for the reduced power.