I've had very good success with one of these, plumbed to a 5 lbs. propane bottle and some 4" aluminum ducting. If you get the accordion style ducting, you can adjust the length based on the OAT so as to not trip the overheat sensor. One thing to remember about forced air heating is to allow an exit for the heated air, you want flow through the nacelle, no stagnation.

https://www.ryobitools.com/products/details/33287177509

robby wrote:

mtv wrote:Try it out and see how it works, then report back. Heating sucks the life out of batteries. It’s not the instantaneous load, it’s a high load for a long time.

Might work in relatively warm temps.

On a different note:

If you’re using a generator to preheat, and it’s COLD, that generator may not starttill you warm IT. Also,I’ve seen a Honda 2000 destroyed because it didnt have the “cold weather kit”.

As I noted in another thread, there’s cold, and then there’s no shit cold. Lots of stuff refuses to work in no shit cold.

MTV

Is there a thread for preheating generators to preheat planes? j/k

I agree about your phases of cold. Part of what makes this project appealing is it gives me a way to warm my engine even on those late fall/early spring days where I could start it no problem at 30-40 F, but would much rather not. I don't anticipate getting into a cold-soaked plane at -15 F but it would be reassuring to know I could if I were otherwise stranded.

I'll report back when I get around to trying this.

First, at those temps, I wouldn’t bother pre heating….well, MAYBE at 30 degrees F…..but probably not.

But here’s the problem with pre heating: the parts that really need the heat are at the core of the engine, crankshaft, camshaft and associated parts. And to pre heat THOSE parts, you’ll have to apply heat for a fairly long period of time. It takes a while for that heat to reach and penetrate with warmth those parts..

Short pre heats just heat the exterior of the engine, not the core. Now, you may do some good there in relatively warm temps by applying pre heat for a fairly short time, then wrapping the engine in an insulated cover while it heat soaks. That takes time, and patience.

But, yes, pre heating at warmer temps is easier, but remember, you can’t rush it, you want those expensive and critical internals warmed, not just the engine case.

MTV

mtv wrote:

robby wrote:

mtv wrote:Try it out and see how it works, then report back. Heating sucks the life out of batteries. It’s not the instantaneous load, it’s a high load for a long time.

Might work in relatively warm temps.

On a different note:

If you’re using a generator to preheat, and it’s COLD, that generator may not starttill you warm IT. Also,I’ve seen a Honda 2000 destroyed because it didnt have the “cold weather kit”.

As I noted in another thread, there’s cold, and then there’s no shit cold. Lots of stuff refuses to work in no shit cold.

MTV

Is there a thread for preheating generators to preheat planes? j/k

I agree about your phases of cold. Part of what makes this project appealing is it gives me a way to warm my engine even on those late fall/early spring days where I could start it no problem at 30-40 F, but would much rather not. I don't anticipate getting into a cold-soaked plane at -15 F but it would be reassuring to know I could if I were otherwise stranded.

I'll report back when I get around to trying this.

First, at those temps, I wouldn’t bother pre heating….well, MAYBE at 30 degrees F…..but probably not.

But here’s the problem with pre heating: the parts that really need the heat are at the core of the engine, crankshaft, camshaft and associated parts. And to pre heat THOSE parts, you’ll have to apply heat for a fairly long period of time. It takes a while for that heat to reach and penetrate with warmth those parts..

Short pre heats just heat the exterior of the engine, not the core. Now, you may do some good there in relatively warm temps by applying pre heat for a fairly short time, then wrapping the engine in an insulated cover while it heat soaks. That takes time, and patience.

But, yes, pre heating at warmer temps is easier, but remember, you can’t rush it, you want those expensive and critical internals warmed, not just the engine case.

MTV

Agreed in terms of combatting overall engine wear. I've got a different problem though, which is that our primer was taken out as part of our 180HP conversion, making it extra difficult to get the engine running in subfreezing temps. Even at 30F you need to time and pump the throttle exactly right. So, the cylinder heat goes a long way even if it's not all that protective, and at the very least it reduces cranking.

Replace the primer. Using the accelerator pump to prime in cold weather is an invitation to a backfire, and a fire.

Why in hell would any mechanic remove a primer system, especially in cool country?

MTV

Agreed in terms of combatting overall engine wear. I've got a different problem though, which is that our primer was taken out as part of our 180HP conversion, making it extra difficult to get the engine running in subfreezing temps. Even at 30F you need to time and pump the throttle exactly right. So, the cylinder heat goes a long way even if it's not all that protective, and at the very least it reduces cranking.

WTF; did the STC specifically require its removal, if not replace it immediately

skiermanmike wrote:I park outside but have electrical, so I do a SwitchBox connected to a Reiff system. When it works, it works great (the SwitchBox is finicky). However, I think I’m going to lose that electrical when the airport reconfigures the hangars in the next couple of years. I’ve been thinking that the perfect solution is a remote-start generator. Is anyone aware of such a thing? The only ones I have found have required WiFi, which isn’t workable if you don’t have power in the first place... anyone?

They do make them remote start or you could use a bunk heater like they use in semi trucks (espar) you can run them with a cell phone but you will still need power to charge a battery.

mtv wrote:Replace the primer. Using the accelerator pump to prime in cold weather is an invitation to a backfire, and a fire.

Why in hell would any mechanic remove a primer system, especially in cool country?

MTV

Could it be because his 180 hp conversion included fuel injection which utilizes the primer ports in the cylinders?

I've had good success with cheap Chinese diesel heaters.

The good
They run on diesel and 12v power (I have a battery and small solar panel).
They are forced air.
They don't use exhaust gas to heat - humid and may have sparks.
They have timers to auto start (not easy to use).

The bad
They are stinky
They are about as noisy as a generator
They are cheap Chinese design and construction.

On The Fly wrote:

mtv wrote:Replace the primer. Using the accelerator pump to prime in cold weather is an invitation to a backfire, and a fire.

Why in hell would any mechanic remove a primer system, especially in cool country?

MTV

Could it be because his 180 hp conversion included fuel injection which utilizes the primer ports in the cylinders?

His profile says Cessna 172 with Avcon 180 hp conversion, which is carbureted.

MTV

mtv wrote:Replace the primer. Using the accelerator pump to prime in cold weather is an invitation to a backfire, and a fire.

Why in hell would any mechanic remove a primer system, especially in cool country?

MTV

Thanks, I’ll discuss with my A&P next time it’s in for maintenance. In fairness to the mechanic who did the work, the plane was being operated in Florida at the time of the conversion.

Mapleflt wrote:WTF; did the STC specifically require its removal, if not replace it immediately

I can’t tell. There is no primer in the Avcon description or drawings, but the paperwork is so sparse that I don’t know what to make of that. Part of the instructions do involve ripping out the old fuel system, including the mechanical and electric pumps, and replacing it all with a purely gravity-fed system. Could that have something to do with it?

mtv wrote:

On The Fly wrote:Could it be because his 180 hp conversion included fuel injection which utilizes the primer ports in the cylinders?

His profile says Cessna 172 with Avcon 180 hp conversion, which is carbureted.

MTV

Correct, it’s a 172N, Avcon conversion O-360, fixed pitch.

I used this STC for the installation of an 0-360 in my 170B. Nothing pointed to removal of the engine primer, I also converted to the gravity fuel system as well. You're going to really like the 0-360 performance, it's the closest I'll ever get to a 180 in my snack bracket.