SB M20-345

[67 m20F chump]

04E3A27F-78A3-4C64-B27B-49F03C2198F6.M20_345.pdf

 

[Ragsf15e]

Got a whole long thread going on the sb

 

[67 m20F chump]

Sorry I didn’t see it by posted.  I have #84 from 67’ and it has one of the bad weights on it.

[Ragsf15e]

4 minutes ago, 67 m20F chump said:

Sorry I didn’t see it by posted.  I have #84 from 67’ and it has one of the bad weights on it.

Sorry to hear that. I was wondering when we would hear about one.  I have a ‘68F and several others have late ‘67s and none of us have the bad weights.

Is yours cracking?

[Raymond J1]

I have the number 26 from the end of 1966 (model 67), they are in very good condition.

[Aerodon]

I have some M20K balance weights that might fit, Ill go look for them.

Aerodon 

[Pinecone]

Need to make sure they are the same weight (as in ounces).

There is a difference in them from a 252 to an Encore.

[67 m20F chump]

Looks like the one in the SB

[A64Pilot]

2 hours ago, Pinecone said:

Need to make sure they are the same weight (as in ounces).

There is a difference in them from a 252 to an Encore.

I assume there is a VNE difference too? if not maybe they wanted a larger margin. Heavier balance weights increase flutter resistance, but there is also a structural limit as to how much weight the elevator can tolerate, so there are limits as to how much weight you can put on an elevator to put it within balance limits. I’ve never looked but the maintenance manual should tell you how heavy a weight you can use.

If I had bad weights and could find good weights within the allowable max, I’d sure acquire them. I’d even be tempted to put a good weight on a diet.

Maybe I’m over reacting, but we don’t know when replacement weights will be available do we?

[67 m20F chump]

I also looked in my manual about balancing it.  It’s a small window to hit.  This is going to be sporty.

[A64Pilot]

38 minutes ago, 67 m20F chump said:

I also looked in my manual about balancing it.  It’s a small window to hit.  This is going to be sporty.

It’s really not that hard if you can remove or add a little weight at a time, aircraft i used to build we had a stack of big washers like fender washers with three holes drilled in them for the attachment screws, they went inside of the end of the flight control, you could also use a half washer if needed.

I’ve never balanced a Mooney flight control, but surely you can add weights to the factory weight, and I’m sure maybe trim its tail to reduce weight if needed.

If I was balancing one I’d be sure to balance to the heaviest weight allowed because no flight control I’ve ever seen loses weight on its back half, from paint touch ups and possibly a repair they always get tail heavy.

Its actually pretty easy to do once you get whatever jig the book wants set up.

On edit, you can usually have it set up in the jig and if weight needs to be added you can stack washers, pennies whatever until it balances, then weigh the pennies or whatever and you’ll have a real good idea of how much weight needs to be added.

 

[Utah20Gflyer]

I checked my plane today, it's a G but you never know what kind of shenanigans might have happened in the past.  Mine were solid units and looked good.  I looked at the F model parked next to me and his were the same as mine.  I don't imagine this is going to affect many people.  

[Guest]

3 hours ago, A64Pilot said:

It’s really not that hard if you can remove or add a little weight at a time, aircraft i used to build we had a stack of big washers like fender washers with three holes drilled in them for the attachment screws, they went inside of the end of the flight control, you could also use a half washer if needed.

I’ve never balanced a Mooney flight control, but surely you can add weights to the factory weight, and I’m sure maybe trim its tail to reduce weight if needed.

If I was balancing one I’d be sure to balance to the heaviest weight allowed because no flight control I’ve ever seen loses weight on its back half, from paint touch ups and possibly a repair they always get tail heavy.

Its actually pretty easy to do once you get whatever jig the book wants set up.

On edit, you can usually have it set up in the jig and if weight needs to be added you can stack washers, pennies whatever until it balances, then weigh the pennies or whatever and you’ll have a real good idea of how much weight needs to be added.

 

No fine tuning the balance with additional washers.  Heavier weights are supposed to be used, or trimming the weight to lighten it.

[EricJ]

4 hours ago, 67 m20F chump said:

Looks like the one in the SB

Ouch.   No bueno.

 

[A64Pilot]

I understand you don’t add washers to a Mooney, I was using the Thrush as an example.

But you can use washers, pennies or whatever to see how much weight you need to add, or subtract for that matter, just measure the arm where the weight will be removed, stack weights on the opposite arm until it balances, remove the pennies or whatever and weigh them. 

Stack them on the center of the weight to see how much to add

It’s a simple balance thing.

[Aerodon]

7 hours ago, Pinecone said:

Need to make sure they are the same weight (as in ounces).

There is a difference in them from a 252 to an Encore.

Yes, the Encore weights are considerably bigger and about 1lb heavier, thats why I have a set of original 252 weights.   They are solid lead, first step is to see if the 3 mounting holes fit.  Then check if the elevators balance within the correct range.  

If anyone is searching for replacement weights, send me an email - supercub180@gmail.com

 

Don

 

 

[PT20J]

Seems like it wouldn’t be that difficult to make a wooden pattern by copying a good one. I wonder how hard it would be to find a small foundry to sand cast them for an OPP?

[Shadrach]

3 hours ago, PT20J said:

Seems like it wouldn’t be that difficult to make a wooden pattern by copying a good one. I wonder how hard it would be to find a small foundry to sand cast them for an OPP?

A lot of high schools used to have foundries for “industrial arts” class. I wonder how many still do. I went to middle school in New Braunfels, TX. In 7th grade we learned sand casting, oxy acetylene and Arc welding among other things.

[67 m20F chump]

It would be working with lead.  I’m not interested in doing that.  I think I will wait on Mooney to make the part.  I think they have a contractor in mind.  The guy I talked with at Mooney said they thought it would be 100 or so planes that had the problem weight.  Maybe I will call them Monday and see if they have a wag on how long they think it will be.

[ilovecornfields]

5 hours ago, Shadrach said:

A lot of high schools used to have foundries for “industrial arts” class. I wonder how many still do. I went to middle school in New Braunfels, TX. In 7th grade we learned sand casting, oxy acetylene and Arc welding among other things.

I think few do. I had the same in 8th grade although we weren’t allowed to pour the molten aluminum into the cast. Watching people try to strike the arc was always fun. 9/10 times it would just stick the the metal.

A few years later they replaced the metal shop with an “electronics lab.”

[Shadrach]

6 hours ago, ilovecornfields said:

I think few do. I had the same in 8th grade although we weren’t allowed to pour the molten aluminum into the cast. Watching people try to strike the arc was always fun. 9/10 times it would just stick the the metal.

A few years later they replaced the metal shop with an “electronics lab.”

I had a similar experience. We weren’t allowed to touch the crucible either.  I could run a reasonable bead with a stick welder after several weeks.  We did some electronics (circuits, capacitors, AC vs DC) and technical drawing as well. Looking back, it was a pretty sophisticated resource for middle school. Even in Texas, people made jokes about taking “shop”.

[PT20J]

This place was a lot of fun when I lived in the SF Bay area. https://www.thecrucible.org

[Guest]

I’ve always thought that the removal of various shop classes in high school was a reason for the lack technical tradesmen now and the loss of manufacturing in North America.

[A64Pilot]

15 minutes ago, M20Doc said:

I’ve always thought that the removal of various shop classes in high school was a reason for the lack technical tradesmen now and the loss of manufacturing in North America.

It’s a symptom of the disease, the disease being the belief that everyone needs a College education, often liberal arts.

Germany had a much better system, in I think 8th grade you “tracked”, some went College track, many went Trade School track, they worked with local industries but also regular school, by the time you graduated you were a Journeyman machinist, welder, electrician etc, and almost always had a job very often at the place you were already training at, if you were good enough.

[N201MKTurbo]

3 minutes ago, A64Pilot said:

It’s a symptom of the disease, the disease being the belief that everyone needs a College education, often liberal arts.

Germany had a much better system, in I think 8th grade you “tracked”, some went College track, many went Trade School track, they worked with local industries but also regular school, by the time you graduated you were a Journeyman machinist, welder, electrician etc, and almost always had a job very often at the place you were already working at

The problem with this model is the engineers have no practical experience. It doesn't always make for the best designs. Especially the younger ones these days. They think they are perfect when they come out of school. They think their designs are the best ever, but they would have a hard time fixing a bicycle.