Harvard/Texan Prop
Join Date: Jan 2007
Location: Australia
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One of the instructors at Claresholm party piece was to take a student on the low flying exercise area and ask the student to show him some low flying. After a few minutes the instructor would say, "I have control" and push the nose down. Having frightened the poor student he would say, "that is low flying".
One day he returned to the flight line with the tips of the prop bent back about thirty degrees. If you look at the length of a Harvard prop blade I would say, "that was low flying"
One day he returned to the flight line with the tips of the prop bent back about thirty degrees. If you look at the length of a Harvard prop blade I would say, "that was low flying"
However, mathematics have improved since them and I'm willing to be corrected!
I calculate that a 9' prop at 2600 rpm would have a tip speed of 835 mph, which would be about Mach 1.1 at sea level.
Of course, my mathematical ability might have been affected by the noise from my ride in "Harvard 98" at Tauranga in January.
A quick cross-country to Matamata gliding club for a cup of tea, followed by aerobatics over the beach. My wife said I couldn't wipe the smile off my face all day. Of course, the earlier ride in "Stearman 03" helped too!
India Four Two
OK I stand corrected on the tip speed reaching 835mph at 2600rpm. But that puts me in a quandary as to why all the arguments I had with others about the prop tip NOT reaching the speed of sound all those many years ago should be changed.
So a small request - show us the math you used to get to your result - please, if only to put me out of my misery!
PS. I'm very envious of your recent ride - last time I stepped out of a Harvard was in 1953.
I'm also struck by the similarity of the fuselage number to the numbering used at 5 FTS back in the early 1950's (see my photo above).
OK I stand corrected on the tip speed reaching 835mph at 2600rpm. But that puts me in a quandary as to why all the arguments I had with others about the prop tip NOT reaching the speed of sound all those many years ago should be changed.
So a small request - show us the math you used to get to your result - please, if only to put me out of my misery!
PS. I'm very envious of your recent ride - last time I stepped out of a Harvard was in 1953.
I'm also struck by the similarity of the fuselage number to the numbering used at 5 FTS back in the early 1950's (see my photo above).
Diam=9ft, circ=pi.d=28.28ft; Max rpm(normal)2250=37.5 rpsec.
28.28 x37.5=1060 ft/sec=.949M..
At 2600 rpm<20 secs(max) =43.3 rpsecs.=43.3 x28.28 =1225 ft/sec=1.1M
Add a vector for 90 KTS on t/o,tipspeed=1070 fps/ .958M.
Add a vector for 200kts @ 2600rpm,tip-speed=1255 fps/ 1.124 M
28.28 x37.5=1060 ft/sec=.949M..
At 2600 rpm<20 secs(max) =43.3 rpsecs.=43.3 x28.28 =1225 ft/sec=1.1M
Add a vector for 90 KTS on t/o,tipspeed=1070 fps/ .958M.
Add a vector for 200kts @ 2600rpm,tip-speed=1255 fps/ 1.124 M
Join Date: Feb 2005
Location: flyover country USA
Age: 82
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Actually the BT-13 Vultee Vibrator was a bit noisier. Same p/n blades, slightly different hub for the Wasp Jr. prop shaft. The Wasp Jr. turned 2300 RPM (vs the Wasp 2200) - and the BT-13 had two-position prop control (no prop governor) which meant you could wind it up past 2400 easily.
Airshow pilots in Stearmans used the Wasp Jr. BT-13 powerplant/prop package, and I shudder at the numbers I've hear them winding up to. At least two of them paid the ultimate price for their noisemaking.
Airshow pilots in Stearmans used the Wasp Jr. BT-13 powerplant/prop package, and I shudder at the numbers I've hear them winding up to. At least two of them paid the ultimate price for their noisemaking.
Warmtoast,
Yes, I noticed the number "dyslexia" as well. In fact, I had to do a double check, to make sure it wasn't the same aircraft.
Earlier in the day, I had flown a PT-17 and my instructor let me do three touch and goes. A lovely aircraft, just like a big Tiger Moth. I felt I would be able to solo it quite quickly. The Harvard on the other hand would take me quite a while to become comfortable in. I wasn't able to try landing it, but I did get to start it up. Clearly, you really need three hands, even after you've been shown how to wrap your leg around the stick
Two observations about the Harvard. Firstly, there is no elegant way to enter or exit the cockpit. It would have been rejected if Cavalry officers ran the RAF.
Secondly, why on earth didn't NA put in a cockpit floor? The loose article risk is huge.
Sitting there, looking out at that big roundel took me right back to my UAS Chipmunk days:
A lovely day. Three flights in three radial engined aircraft. I cannot wait to go back. They've got a T37 as well!
Yes, I noticed the number "dyslexia" as well. In fact, I had to do a double check, to make sure it wasn't the same aircraft.
Earlier in the day, I had flown a PT-17 and my instructor let me do three touch and goes. A lovely aircraft, just like a big Tiger Moth. I felt I would be able to solo it quite quickly. The Harvard on the other hand would take me quite a while to become comfortable in. I wasn't able to try landing it, but I did get to start it up. Clearly, you really need three hands, even after you've been shown how to wrap your leg around the stick
Two observations about the Harvard. Firstly, there is no elegant way to enter or exit the cockpit. It would have been rejected if Cavalry officers ran the RAF.
Secondly, why on earth didn't NA put in a cockpit floor? The loose article risk is huge.Sitting there, looking out at that big roundel took me right back to my UAS Chipmunk days:
A lovely day. Three flights in three radial engined aircraft. I cannot wait to go back. They've got a T37 as well!
Done, check your PM's.
Here is pontifex' photo of the Zeke. Wonderful shot.
(I resized it a bit so's it wouldn't be too big for the page.)
Here is pontifex' photo of the Zeke. Wonderful shot.
(I resized it a bit so's it wouldn't be too big for the page.)
Last edited by pigboat; 16th Feb 2010 at 12:36.
