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User avatar
By WaxMax45
#1782751
Good Evening,
please excuse my ignorance, but I seem to be seeing discrepancies within the cessna 150 climb speeds. The 1968 POH says that 57MPH is the best angle of climb speed, whereas the 1969 POH says that 64MPH is the best angle of climb speed, is there really any difference or is it just the newer POH's were more accurate as I don't believe there were any significant changes between the 1968 and 1969 Cessna 150.
User avatar
By Rob P
#1782760
That's very close to a mph / knot transposition.

Odder things have happened.

Is the same difference in climb speeds apparent in the best angle of climb (Vx) figures?

Rob P
User avatar
By WaxMax45
#1782764
yes, i wonder what the difference is caused by though? I don't believe its the use of 10-degree flaps. Perhaps better accuracy in the figures or a safety measure; as the older manuals seem to use Vx much closer to the stall speeds.
User avatar
By Flyin'Dutch'
#1782767
Rob is alluding to the fact that someone may have got their knots and mph mixed up.

57kts = 64mph
User avatar
By WaxMax45
#1782770
Flyin'Dutch' wrote:Rob is alluding to the fact that someone may have got their knots and mph mixed up.

57kts = 64mph

Yes silly me, that makes absolute sense, I thought that at the start, but began to overthink. :roll:
Last edited by WaxMax45 on Sun Jul 12, 2020 9:01 am, edited 1 time in total.
User avatar
By Flyin'Dutch'
#1782772
Well it is well noticed and to further examine it, worthwhile.

Are both official POHs or is one/both a home made one/sheet?
User avatar
By Rob P
#1782774
Sorry I asked the wrong question above.

I meant to ask how do the best rate of climb figures (Vy) of the two different manuals compare?

Rob P
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User avatar
By Flyin'Dutch'
#1782777
@WaxMax45

Where do you find all these POHs?
User avatar
By WaxMax45
#1782778
@Flyin'Dutch'
all official , here are the links: https://jasonblair.net/wp-content/uploa ... 69-POH.pdf
https://www.manualslib.com/manual/10197 ... -1968.html
https://www.kevincfi.com/files/pdf/manu ... Manual.pdf
if they weren't official I would have quickly assumed human error, however this may still be the case.
Last edited by WaxMax45 on Sun Jul 12, 2020 9:02 am, edited 2 times in total.
User avatar
By WaxMax45
#1782780
Rob P wrote:Sorry I asked the wrong question above.

I meant to ask how do the best rate of climb figures (Vy) of the two different manuals compare?

Rob P

they are essentially the same, 1 mph difference, which is why I'm asking about the Vx figures
User avatar
By WaxMax45
#1782782
I understand that the cause may be knot-mph conversion discrepancies between the 1968 and 1969 pohs, however, the 1967 poh says 52mph, which is again fairly different. I think they mean 52 knots ≈ 60Mph
User avatar
By Flyin'Dutch'
#1782787
WaxMax45 wrote:@Flyin'Dutch'
all official , here are the links: https://jasonblair.net/wp-content/uploa ... 69-POH.pdf
https://www.manualslib.com/manual/10197 ... -1968.html
https://www.kevincfi.com/files/pdf/manu ... Manual.pdf
if they weren't official I would have quickly assumed human error, however this may still be the case.


Just had a look and in all three the speed for max rate of climb is 73 mph.

The 64 mph is the speed at 50ft in the take off distance calculator.

HTH
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User avatar
By WaxMax45
#1782801
Flyin'Dutch' wrote:
WaxMax45 wrote:@Flyin'Dutch'
all official , here are the links: https://jasonblair.net/wp-content/uploa ... 69-POH.pdf
https://www.manualslib.com/manual/10197 ... -1968.html
https://www.kevincfi.com/files/pdf/manu ... Manual.pdf
if they weren't official I would have quickly assumed human error, however this may still be the case.


Just had a look and in all three the speed for max rate of climb is 73 mph.

The 64 mph is the speed at 50ft in the take off distance calculator.

HTH

Thankyou, yes I believe that 64mph is Vx. However, the discrepancies are quite interesting.
User avatar
By Flyin'Dutch'
#1782804
Beste rate of climb is Vy = in this aeroplane 73mph
Best angle of climb is Vx = in this aeroplane 64 mph.
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User avatar
By WaxMax45
#1782807
Flyin'Dutch' wrote:Beste rate of climb is Vy = in this aeroplane 73mph
Best angle of climb is Vx = in this aeroplane 64 mph.

Yes, thank you, this is apparent. The 1967 poh must have knot-mph conversion errors.