C-85 Long engine mount or Short

[Hank Jarrett]

Re: C-85 Long engine mount or Short

These are Lithium Iron Phosphate (LiFePO4) batteries and shouldn't be confused with the Lithium batteries in computers (and the new Boeings) that seem to burst into flames at the slightest provocation. They are MUCH more stable but have very high power density (lots of electrons for small weight). The ones the Cub guys are talking about are at http://earthxmotorsports.com/our-batteries/ and there is another supplier at http://www.starkpower.com/.
They look like the next big jump in battery performance. A couple of more jumps and we won't need to discuss how much power we get from a 65, 75, 90 or O-200 anymore. We can just pop a battery in and go fly!
Hank

Make sure if you look at these batteries they have the safety circuits IN the battery. If they don't you need to be sure you charge them right. The ones I have looked at are pretty insensitive to chargers (a good thing), but I haven't looked at the details on all of them.

[Pearson]

Re: C-85 Long engine mount or Short

Rich why not stick with the short mount and do like i did put the battery out on the fire wall. The group on supper cub were talking about a new battery that is just hitting the market that is 620 CCA and only weighs almost 3 LBS. It is 11 LBS. lighter then the oddysey i have on my tcraft witch is 14 LBS. Check post 19 of this thread my CG and weights are there.

I would do that, but the STC requires the long mount in order to raise the gross weight to 1500 pounds, which is what I want to do. I am just not sure how much effect replacing the original style starter and generator with the new lighter weight versions will affect the C.G.

[Robert Lees]

Re: C-85 Long engine mount or Short

I would do that, but the STC requires the long mount in order to raise the gross weight to 1500 pounds, which is what I want to do. I am just not sure how much effect replacing the original style starter and generator with the new lighter weight versions will affect the C.G.

I'm late to this conversation, but to agree with the foregoing: The only way to get a gross weight of 1500lbs without exceeding an aft cg situation is to get some serious weight up front.

The only serious weight is the engine, so stick it on a longer mount & hey ho there you go.

Mind you, the battery gets relocated aft, so I wonder whether Jack Gilberti originally put a non-electric motor on the long mount. Then when demand for the heavy starter/generator arose, he had to balance the battery weight.

So if using a lightweight kit on the engine, be VERY careful about an aft cg situation. You could always use a lightweight Lithium Ion battery in the baggage compartment...I understand Boeing have a few surplus to requirements.

[astjp2]

Re: C-85 Long engine mount or Short

There are 2 337's in the tech reference section on installing the battery on the fire wall, I would not want all of that stored electrical energy under by butt or in the baggage. The Odessey is the way to go if you are ever near cold temps, that other battery has not been fielded much. Tim

[cvavon]

Re: C-85 Long engine mount or Short

Richard the B&C starter and alternator weigh 13.7 LBS the stock Delco weigh25.62 thats 11.92 LBS less. That will change CG some i would think.The oddysey battery is 14 LBS

[Hank Jarrett]

Re: C-85 Long engine mount or Short

Mind you, the battery gets relocated aft, so I wonder whether Jack Gilberti originally put a non-electric motor on the long mount. Then when demand for the heavy starter/generator arose, he had to balance the battery weight.

So if using a lightweight kit on the engine, be VERY careful about an aft cg situation. You could always use a lightweight Lithium Ion battery in the baggage compartment...I understand Boeing have a few surplus to requirements.

A light engine originally with a long mount was probably what he had in mind. There is no reason for 4" of extra length except to get the weight of the engine way forward, much farther than the rear case access would require. Robert hit it on the head, when the extra accessories started to be added he had TOO MUCH engine mount length and had to move a battery aft to get back in CG. With the new light weight starters and alternators you can mount them on the short mount and then put the battery back in front of the kick plate where it was originally.

Just remember that Boeing used Lithium Ion batteries....BAD IDEA without individual cell monitoring with a chip on each cell. The new Lithium Iron batteries have nearly as much power density and are about as small as the Ion batteries without the fire danger. Most come with a chip built in to each cell (MAKE SURE THE BATTERY YOU GET DOES!!) and Lithium Iron batteries can be charged with a lead acid charger just like the original lead acid battery (AGAIN, MAKE SURE YOU GET ONE THAT ALLOWS THIS!)

I WOULD NOT, EVER (REPEAT E V E R) put a Lithium Ion battery in an airplane! There is NO PLACE to run away from it, the fumes are toxic and it is too hot to even throw out of the plane. I don't even like the ones in the GPS units and radios. I use NiCd batteries in my carry on equipment or flash light batteries (carbon dry cells). At least when a NiCd overheats you can throw it out the window and the fumes won't kill you (right away).

Hank

Yea, I was on the NASA subject matters expert list for batteries when I was at NESC too. I have had WAY too many jobs.

[astjp2]

Re: C-85 Long engine mount or Short

Battery will need to be PMA'd, most GA manufacters will not spend the money to get that LiON PMA for a few more years, you are stuck with the oddessey if you want a light weight battery.

A light engine originally with a long mount was probably what he had in mind. There is no reason for 4" of extra length except to get the weight of the engine way forward, much farther than the rear case access would require. Robert hit it on the head, when the extra accessories started to be added he had TOO MUCH engine mount length and had to move a battery aft to get back in CG. With the new light weight starters and alternators you can mount them on the short mount and then put the battery back in front of the kick plate where it was originally.

Just remember that Boeing used Lithium Ion batteries....BAD IDEA without individual cell monitoring with a chip on each cell. The new Lithium Iron batteries have nearly as much power density and are about as small as the Ion batteries without the fire danger. Most come with a chip built in to each cell (MAKE SURE THE BATTERY YOU GET DOES!!) and Lithium Iron batteries can be charged with a lead acid charger just like the original lead acid battery (AGAIN, MAKE SURE YOU GET ONE THAT ALLOWS THIS!)

I WOULD NOT, EVER (REPEAT E V E R) put a Lithium Ion battery in an airplane! There is NO PLACE to run away from it, the fumes are toxic and it is too hot to even throw out of the plane. I don't even like the ones in the GPS units and radios. I use NiCd batteries in my carry on equipment or flash light batteries (carbon dry cells). At least when a NiCd overheats you can throw it out the window and the fumes won't kill you (right away).

Hank

Yea, I was on the NASA subject matters expert list for batteries when I was at NESC too. I have had WAY too many jobs.

[swoeric]

Re: C-85 Long engine mount or Short

long mount 85
odessey on firewall
b&c alt
heavy starter
Al prop
30in tires
disc brake
scott 3200 out back


noticeably nose heavy

hopefully catto prop and new starter possibly no starter will balance out...yes i could do the math but havent.... chuck has all of the numbers if somebody wanted to let me know how much more i need to spend to get it right.

ill probably add some windows to the rear and weigh kydex vs wood for baggage. ace in the hole will be baby bushwheel, pod or lumber rack.

Removing the 35lb batt was one thing the 15-20 lbs of welding cable front to back was equally impressive...

now to just squeeze 0360 cyl on the 0200

[astjp2]

Re: C-85 Long engine mount or Short

Use a Gar Aero tail wheel! Adds a few pounds to the back,and its called an IO240......Tim

long mount 85
odessey on firewall
b&c alt
heavy starter
Al prop
30in tires
disc brake
scott 3200 out back


noticeably nose heavy

hopefully catto prop and new starter possibly no starter will balance out...yes i could do the math but havent.... chuck has all of the numbers if somebody wanted to let me know how much more i need to spend to get it right.

ill probably add some windows to the rear and weigh kydex vs wood for baggage. ace in the hole will be baby bushwheel, pod or lumber rack.

Removing the 35lb batt was one thing the 15-20 lbs of welding cable front to back was equally impressive...

now to just squeeze 0360 cyl on the 0200

[Pearson]

Re: C-85 Long engine mount or Short

long mount 85
odessey on firewall
b&c alt
heavy starter
Al prop
30in tires
disc brake
scott 3200 out back


noticeably nose heavy

So Eric, if you were to move your Odessey battery to the aft end of the baggage compartment, would that put your C.G. close to the sweet spot? If you could provide me with the weight of the battery and the arm that it is currently located at, I could calculate the effect on the C.G. of moving it to the aft baggage compartment.

[cvavon]

Re: C-85 Long engine mount or Short

Ok with a B&C starter you would pick up 5.20 lbs over stock starter, switch to catto prop will get you about 8 to 10 lbs, the oddessey battery is 14 lbs plus the box about 1lb. With the set up on 26658 B&C starter,alternator, oddessey battery on fire wall aluminum prop 26 in bush wheels AK Bush 3200 tail wheel disk brakes SHORT MOUNT cg is 18.95 at a weight of 777 lbs. The 15 lbs you will get back by adding the light starter and wood prop should help as it is all on the very front of the plane.Eric if you feed the dogs more and put them in the back CG will be just right.

[swoeric]

Re: C-85 Long engine mount or Short

keeping the batt on the firewall due to less elec in the cabin. much less weight in wire... 40lbs in aft baggage is about right maybe a touch more....Yep io240 is where i was headed but maybe a just real light weight 320 will do.....Great idea on gar aero tailwheel plus im sure ill add a tail hook for fun and a couple more pounds way back there...

TTail hook is cheapest and easiest so ill start there.. I have a feeling i will have way more fun with a prop than i will with a new starter or just may try a short swing out mount....ok os the short swing mount might be first if it gets me close

[Forrest Barber]

Re: C-85 Long engine mount or Short

We did a lot of scratching our heads when building the F-19 ; remember that was the ONLY engine close to the C-85 at that time. The 4 in. was to accomadate the C-85-12F accessories . We did a swing out mount here one time with buttons into the firewall. If you need wt aft ; yes tow hook is good, large tailwheel, battery can be put lots of places . I too like firewall. Gross Wt has to do with structure AND horsepower .... Check your TC 696 evolution into the TC1A9 ..... BC12D-4-85 vs. Model 19 ; all mods can be based upon making the ship the "equivalent" of the already certified aircraft.

hope all is well at SNF