Congrats on the C170. You picked up a beauty. Welcome to the world of the taildragger. I look forward to the upcoming YouTube adventures.



Josh

Nice looking 170! I remember seeing that for sale in the Boise area a few months ago, glad it has a new owner! I'm in North Idaho if you ever get over this way and do any backcountry flying!

motoadve wrote:Is there an STC for an extended baggage compartment with the battery mounted on the back?

I do not believe that there is. You would have to modify one of the existing extended baggage STC's, and that probably is going to be more work than it's worth to get approved. When we installed ours, we used the Selkirk one (the Airglass version had not been approved yet at the time) and we asked about it. It seems like Selkirk was open to us modifying it to accommodate the battery, but they didn't have an STC for the modification, or any approved data for the modification, so our FSDO said no. But our FSDO says no to everything. We probably could have hired a DER to try to get it done, but there's no guarantee that would work, and it would be expensive- probably. We ended up using the Selkirk extended baggage kit as is, and moving our battery to the firewall with the smaller Odyssey battery. We also pulled out some old instruments at the same time, including the vacuum pump, and the weight and balance change was pretty minimal.

amacbean wrote:

motoadve wrote:Is there an STC for an extended baggage compartment with the battery mounted on the back?

I do not believe that there is. You would have to modify one of the existing extended baggage STC's, and that probably is going to be more work than it's worth to get approved. When we installed ours, we used the Selkirk one (the Airglass version had not been approved yet at the time) and we asked about it. It seems like Selkirk was open to us modifying it to accommodate the battery, but they didn't have an STC for the modification, or any approved data for the modification, so our FSDO said no. But our FSDO says no to everything. We probably could have hired a DER to try to get it done, but there's no guarantee that would work, and it would be expensive- probably. We ended up using the Selkirk extended baggage kit as is, and moving our battery to the firewall with the smaller Odyssey battery. We also pulled out some old instruments at the same time, including the vacuum pump, and the weight and balance change was pretty minimal.

That's a good point.... Since you're adding some weight in the form of the extended baggage compartment aft, but removing the stock battery, and adding a much lighter battery on the firewall, there may be a few other things you could do to keep the CG pretty close. Also, you MAY be able to convince a mechanic to create a new mount for the battery aft, using the Odyssey battery, but with no box, since one isn't required with that battery. Mounting the Odyssey actually could be pretty simple back there. Then the loss of weight from the battery would just about equal the addition of weight of the extended baggage compartment.

MTV

mtv wrote:

amacbean wrote:

motoadve wrote:Is there an STC for an extended baggage compartment with the battery mounted on the back?

I do not believe that there is. You would have to modify one of the existing extended baggage STC's, and that probably is going to be more work than it's worth to get approved. When we installed ours, we used the Selkirk one (the Airglass version had not been approved yet at the time) and we asked about it. It seems like Selkirk was open to us modifying it to accommodate the battery, but they didn't have an STC for the modification, or any approved data for the modification, so our FSDO said no. But our FSDO says no to everything. We probably could have hired a DER to try to get it done, but there's no guarantee that would work, and it would be expensive- probably. We ended up using the Selkirk extended baggage kit as is, and moving our battery to the firewall with the smaller Odyssey battery. We also pulled out some old instruments at the same time, including the vacuum pump, and the weight and balance change was pretty minimal.

That's a good point.... Since you're adding some weight in the form of the extended baggage compartment aft, but removing the stock battery, and adding a much lighter battery on the firewall, there may be a few other things you could do to keep the CG pretty close. Also, you MAY be able to convince a mechanic to create a new mount for the battery aft, using the Odyssey battery, but with no box, since one isn't required with that battery. Mounting the Odyssey actually could be pretty simple back there. Then the loss of weight from the battery would just about equal the addition of weight of the extended baggage compartment.

MTV

Mike thanks , I think this is a good solution.
Anyone can share the link of the Odyssey battery that works with the C170?

SBS J-16 is the battery you want.

A1Skinner wrote:SBS J-16 is the battery you want.

Thank you

Nice score Larry. Keeping the CJ? Can't wait to see it at the next STOL BBQ (or sooner).

aftCG wrote:Nice score Larry. Keeping the CJ? Can't wait to see it at the next STOL BBQ (or sooner).

Yes keeping the CJ, that plane is super fun.

You may want to correct the W&B or reweigh the airplane.
It appears that there is an error in the W&B calculation:
https://media.sandhills.com/doc.axd?id= ... VX9MDHc%3D

AKclimber wrote:You may want to correct the W&B or reweigh the airplane.
It appears that there is an error in the W&B calculation:
https://media.sandhills.com/doc.axd?id= ... VX9MDHc%3D

Yes that one has an error, have the corrected version now.

motoadve wrote:

AKclimber wrote:You may want to correct the W&B or reweigh the airplane.
It appears that there is an error in the W&B calculation:
https://media.sandhills.com/doc.axd?id= ... VX9MDHc%3D

Yes that one has an error, have the corrected version now.

Good deal.
When I bought my 170B, there were lots of errors in the W&Bs calculations that accumulated over the years. The paper CG was so far forward that it was impossible to bring it within the envelope and stay within gross weight. I don't think the previous owner ever did a W&B, but he did agree to have it reweighed after I pointed it out, and all was good.

AKclimber wrote:

motoadve wrote:

AKclimber wrote:You may want to correct the W&B or reweigh the airplane.
It appears that there is an error in the W&B calculation:
https://media.sandhills.com/doc.axd?id= ... VX9MDHc%3D

Yes that one has an error, have the corrected version now.

Good deal.
When I bought my 170B, there were lots of errors in the W&Bs calculations that accumulated over the years. The paper CG was so far forward that it was impossible to bring it within the envelope and stay within gross weight. I don't think the previous owner ever did a W&B, but he did agree to have it reweighed after I pointed it out, and all was good.

Many years ago I took my commercial check ride in a 180hp Arrow. I was warned by fellow students in the school to watch the W&B because with two people in the front seats and full tanks it would (according to the W&B) be beyond aft CG limits. Seemed preposterous but you don't just say that to a DPE and strap in. I think the school eventually reweighed the plane and corrected it.

What a dog that plane was. It was where I learned the real meaning of "positive rate" because that's about all you could say about the climb rate. Its power off glide was similar to a man hole cover. From the 180 degree position you had to dive for the numbers or die. Good times.

I am just doing a O-360 conversion and I will be weighing the plane. I have always been extremely skeptical about paper weight and balance figures which have been extrapolated from a 20 or more year old weighing.

I think with the high wing Cessnas they are so forgiving that we tend to get complacent. Sure fly differently though, and how fast the tail comes up is probably not the safest way to calculate CG.

daedaluscan wrote:I am just doing a O-360 conversion.

Congrats, Man. You've been wanting that for a while IIRC. Enjoy! And to the OP, Congratulations as well. Looks like a fine bird.
-DP