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J5A Cub Cruiser

T

tonyboullemier

Registered User
Hi friends !

My club operates a 1941 J5A Cub Cruiser with O-235 Lycoming 105hp. We are in need of some accurate take-off and landing performance data ( graphs ) and if possible an original Piper CofG envelope illustration.

Thanks in anticipation.
 
You are asking for a unicorn, that performance data simply does not exist. The TCDS contains the CG envelope, however you have an airplane that was modified to install the O-235. The J5A originally had a Continental A75. You need to find the data (STC or otherapproved data) that made the change to see if it changed the CG range. The TCDS can be found on the RGL under FS2001, the current TC owner.

As for performance data, this is a CAR 4 airplane.the only performance data is that the airplane needed to show compliance to CAR 4.7010, land planes need to be able to takeoff in 1000’ at gross weight standard day sea level with no wind.


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If the "club" does not have a good pilot then go find one. Now take the plane out and fly it. Fill out performance data as needed. I have shown my planes all sorts of performance data information and they just seem to do what they want too.
DENNY
 
Thanks fellas - initial answers seem to confirm what we thought insomuch that there are no official figures or graphs for the modified type. We can find information for the J3,L4 and Super-Cub without any difficulty but not for the J5. We are taking a common sense approach using interpolation and factoring as appropriate but clearly its not quite the same as manufacturer figures. We fully accept that the aircraft is old and that things were done differently back in the day. Loading and C of G information we have which is sanctioned by the regulatory body but an example of an original J5 envelope would be interesting to compare notes.

Thanks again Ll
 
My 1943 J5C with a 100hp O235 did pretty well...
if memory served me it weighted around 940 lbs
72/38 prop
In the Valdez competition seems I took off and landed in the 170’ range...20 gal of fuel at 75’ sea level.

Off Airport with gear and 20-30 gal of fuel it was comfortably a 400-500’ plane...one of the best flying cubs I have ever owned.
 
dgapilot said:
You are asking for a unicorn, that performance data simply does not exist. The TCDS contains the CG envelope, however you have an airplane that was modified to install the O-235. The J5A originally had a Continental A75. You need to find the data (STC or otherapproved data) that made the change to see if it changed the CG range. The TCDS can be found on the RGL under FS2001, the current TC owner.

As for performance data, this is a CAR 4 airplane.the only performance data is that the airplane needed to show compliance to CAR 4.7010, land planes need to be able to takeoff in 1000’ at gross weight standard day sea level with no wind.


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Click to expand...
Chances are this was approved by form 337 dated prior to October 1,1955. I believe I have a copy of an original on microfiche.
 
skywagon8a said:
Chances are this was approved by form 337 dated prior to October 1,1955. I believe I have a copy of an original on microfiche.
Click to expand...

That’s why I indicated “or other approved data”.

For the OP, if you want data for performance I would suggest you do some flight testing to establish some known points, then get copies of the Roncz spreadsheets and play the variables until the spread sheet gives thee numbers from your test points, then use the spread sheets to generate your performance tables.


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I just looked at the original 337 which was approved by CAA engineering on March 20,1953 for this engine conversion. There is no performance data provided.
 
Heck, the 1965 Champion 7ECA I used to own had no Owners' Manual, POH, or any other "performance" information. Just a placard in the plane that said don't exceed 130 mph inverted... I created my own, based (loosely) off the similar (but higher-powered) O-235 engined 7ECA from a few years later, and then did a bunch of flight tests to validate those numbers. Landing distances were pretty close, but all the "in-flight" data was slower-than-predicted, likely because my engine and prop were a bit "tired" compared to a new plane.
 
Precisely why we are trying to put together an unofficial POH for 'guidance only' so that new converts to the aeroplane have something they can look at on those days when the cloudbase is too low or the wind is out of limits. Sure, we can start building a database of take-off distances and landing ground roll but these figures would not be 'manufacturer accurate' and that is why we simply ask the question if there is any information out there that was published by Piper. It appears that there is not from most of the replies so far !
 
Like other old planes my J3 also didn't come with any "performance" figures; just have to take off and climb at different speeds to see what works. Weight and balance is limited to "if it fits in the tiny little baggage and you solo from rear you're within weight and balance".

We have to also consider this is for a flying club. Many clubs require pilots to fill out weight and balance sheets as well as weather briefings for the local airports and those on planned route. It's all for insurance reasons. This is probably why OP needs these figures, not because of any lack of piloting skill.
 
Crash

We certainly go through the issues of weight and balance with all our converts as we do have the relevant information. What we don't have is 'performance'. This does not present a major problem with experienced pilots or those with plenty of time on type but for a newbie straight from a 150 or a 28 they do not have the feel for stick and rudder nor an instinct for the aircrafts capabilities - that will come in time but as a consequence training and subsequent solo time needs to be closely monitored.
 
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