67 F model vs 85 J model

[Tim Jodice]

I am buying a J model and the one I am currently looking at doesn't seem to go as fast as it should. I say that because I have about 250 in a F that goes as fast as the J. I have done a 4 way gps in the J.

 https://flightaware.com/live/flight/N5812T/history/20191013/1815Z

I plan to do one in the F today.

I dropped the  J of last night then took th F back home.

https://flightaware.com/live/flight/N5812T/history/20191015/2122Z/KASH/L 43.08110 -76.52940

https://flightaware.com/live/flight/N6390Q/history/20191016/0004Z

It looks like they are about the same speed.

Neither have any speed mods. The J has TKS

The F has a 600 hrs engine the J 170 hrs both done by Penn Yan. 

The F has a square tip Hartzell, the J a elliptical tip Macauley. I dont know if they are the stock propellers. 

Reading on here I has found most say an F model is good for 150 knots and a J 160.

Any thoughts?

[N201MKTurbo]

I had an F for 19 years and have had a J for 16 years. The J has a turbo, so it isn't apples to apples, but down low the F would do 152 KTS and the J does 152 KTS

[Tim Jodice]

That's good to hear. I dont care about loosing a few knots but I am concerned that there is a bigger issue causing it. Looking for suggestions as to what would slow it down. I know tks is a few knots.

[carusoam]

Tim,

many Fs have become forever-planes...

They get updated with cowl closures and sloped windshields...

In the end... A J is an F with a few mods...

Some of the nicest Fs around here have been completely reworked and some get TN’d too...

Best regards,

-a-

[Tim Jodice]

4 minutes ago, carusoam said:

Tim,

many Fs have become forever-planes...

They get updated with cowl closures and sloped windshields...

In the end... A J is an F with a few mods...

Some of the nicest Fs around here have been completely reworked and some get TN’d too...

Best regards,

-a-

This F model has no speed mods 

[carusoam]

Some Js didn’t get enough speed mods either...

If you want to have some comparison fun... park next to an Ovation and look at each of the differences...

From cowl, to flap gap seals, to wing tips, to the tightness around the tail feathers...  all really small details for a few knots that combine to make a large difference...

Engine strength is import as well... ignition timing is a part of that...

Best regards,

-a- 

[Tim Jodice]

Stock vs stock shouldn't the J be faster?

[Bob - S50]

Just now, airtim said:

Stock vs stock shouldn't the J be faster?

Yes.

[Tim Jodice]

Would you worry about it? I did the prebuy yesterday and it checked out great, found 6 things and they agreed to fix all of them.

[Andy95W]

Not if you like the airplane.  

Slow speed can be attributed to rigging that isn't quite right, heavier weight, or too many antennas.

[Bob - S50]

Looks to me like the J got an average speed of about 155 KTAS at 5500'.  That's about right.  It all depends on what power setting you were using.  For my '78 J I find that if I run 2600 RPM and LOP, 10 GPH (75%) gives me about 145 KIAS.  At 5500' that would be about 158 KTAS.  9 GPH (about 68%) gives me about 135 KIAS.  At 5500' that would be about 147 KTAS but at 9500' that would be about 156 KTAS.

[carusoam]

The J is a Modified F...

Some guy at Mooney took aerodynamics to the next level... And didn’t change anything else...

See if you can find Roy LoPresti in the Mooney history archives...

 

Then look up all the maintenance things that can make a difference regarding rigging the controls...

The F can be brought up to J speeds... the J can relapse back to F speeds...

Best regards,

-a-

[Bob - S50]

Also, if you are convinced the plane is slow, a mis-timed magneto can make a difference.  I also find that my plane is about 2 knots faster when my wife sits in back vs two people in the front seat.

[thinwing]

Depending on tks install..that could easily be a 5 kt loss...well worth it for the occasional icing encounter

[carusoam]

5 minutes ago, airtim said:

Would you worry about it?

If you are happy with the PPI....

You are getting what you expect to get...

To get the ultimate performance PPI... it helps to seek the top level Mooney pros...

Have DMax fly the plane as part of the PPI process...

Yes, people do this...

The limit to how perfect your Mooney is going to be is very much related to the budget you want to spend, or hours you want to be involved in doing the homework...

 

If you are spending as much as your house costs on your Mooney... get a really good, top level, PPI...

Some people are not familiar with the multiple levels a PPI can have... there is no standard PPI...

If your PPI defines the base line..... no damage, no corrosion, no other surprises... you have a good baseline to start from.  Safety is most important, followed by safety of your wallet...

You spend less on your PPI, but you don’t know what is causing the slowness...

At the other end of the spectrum... the Mooney is already discounted from its brand new price... how much perfection are you expecting to get?

I think there is a well documented east coast race around here somewhere... somebody had a foreverplane F and the other MSer has a forever plane J... the jousting was quite fun for a while...

Best regards,

-a-

[Tim Jodice]

Thank you all for the feed back. Sounds like I am trying to figure out a problem that does not exist. 

I am happy with the prebuy

I am not looking for perfection 

They are motivated sellers and the plane priced accordingly. after flying it I gave them a refundable deposit pending a prebuy inspection. I agreed on there price they agreed to fix everything because I didn't try to beat them down on the normal things that happen to a 30+ year old airplane. I am really excited about the way it is going. Should be mine by the end of the month after they fix the squawk list.

Thank you all.

[KSMooniac]

I'd chalk it up to TKS adding some aero drag and weight. The J is likely noticeably heavier than the F, which hurts speed, especially at forward CG.

Sounds like you're otherwise happy with the plane. Once you get it, you can focus on checking the rigging, including gear doors, baffling and seals, timing, etc. All of those contribute to speed. As does flying on a cold day with an aft CG.

Sent from my LG-US996 using Tapatalk

[Mufflerbearing]

I have FIKI on my M20S and with all of my investigations, I have found that it cost about 4 kts.

Enjoy the J!  Make it a forever plane and just enjoy it!

[MarkD34M]

Airtim:

N5812T?  

[carusoam]

13 hours ago, airtim said:

Stock vs stock shouldn't the J be faster?

Stop the presses!

we are comparing Stock F to Stock J...

We know the J is faster because it has a few aero/speed mods... the stock F didn’t get...

We also know that TKS systems alter the leading edge of the stock wing and are known to generate a 10knot drag at ordinary altitudes, less up high...

 

So are we really comparing stock airframes? or did the OP clearly state that the J has this wonderful anti-ice system that clearly isn’t being accounted for...?

 

Game, Set, Match! 

 

you have just been approved to take the next step... Send the the J to get its PPI done... make sure the TKS system is working properly...

It would suck to end up with speed robbing mods that don’t work properly...

If IFR flying is not your thing, or cold winter flying with rain and ice isn’t either... the TKS system is quite expensive and has a speed penalty... this particular J may be better for somebody else...?

How is that for a PP thoughts, without any mechanical skills...?

Best regards,

-a-

[Tim Jodice]

12 hours ago, MarkD34M said:

Airtim:

N5812T?  

Yes

[steingar]

Difference in trip time between a stock F and a stock J can be measured in minutes.  It isn't night and day.  F's are already pretty fast.

[Vno]

On 10/16/2019 at 10:43 AM, thinwing said:

Depending on tks install..that could easily be a 5 kt loss...well worth it for the occasional icing encounter

I agree. I have TKS on my J and I am 5-7 knots less at lower altitudes than what other non-TKS Js are stating they get. I might have other drag inducing items but the TKS is a big one.

Brian

[Tim Jodice]

1 hour ago, steingar said:

Difference in trip time between a stock F and a stock J can be measured in minutes.  It isn't night and day.  F's are already pretty fast.

Agreed, my regular trip is 120 miles. I dont care about the speed because of the time it saves, I was concerned there was a problem with the airplane causing the speed loss. After all of the responses here (thank you all) I am not worried about it. TKS and 190 pounds heavier empty weight plus the J had full tanks, the F to the tabs. Thanks again.

[MarkD34M]

Airtim:  I send you a PM. I did a lot of research on that plane. I spoke to the engine rebuilder (Pine Mountain) who did the overhaul prior to Penn Yann doing the IRAN. She had Nickel Cylinders done at that time. The install is excellent. I ended up buying an ovation but I liked the plane .........  Good luck! Feel free to call if you would like to chat.