• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Wildcat Cub

comment to add. 2, actually.

1. On your revised nosebowl, have Carbon Concepts beef up the openings fer yer oil coolers so you dont hafta use those sheet metal doublers and Tinnerman nuts and PK screws. 2 layers of X Mat would do it just fine........ or some Carbon extras

2. Is the cold oil gonna be congealed when you decide your oil temp needs reduced and you open the doors? maybe! A firewall mounted solution would solve that problem and get the coolers, oil, controls, and hoses a couple feet behing the nose if that mattered.

comment!

Welcome to experimenting!

Thanks Again! fer posting your stuff
 
The metal doubler is there to reinforce the otherwise fairly soft fiberglass nose bowl. A carbon fiber replacement will have that area beefed up from the start. Like I said earlier, this nose bowl is a prototype.

I don't think congealed oil will be any problem. If it is I'll add Reiff oil cooler heaters. Does Niagra offer a non-congealing cooler like we use on Cessnas? I never thought about it before.
 
The metal doubler is there to reinforce the otherwise fairly soft fiberglass nose bowl. A carbon fiber replacement will have that area beefed up from the start. Like I said earlier, this nose bowl is a prototype.

I don't think congealed oil will be any problem. If it is I'll add Reiff oil cooler heaters. Does Niagra offer a non-congealing cooler like we use on Cessnas? I never thought about it before.

plan was for removable face restrictor plates also, like you do on normal front installs for very cold ops
 
I read where you said this was a prototype.

I dunno about non congealing coolers of that style.

I see the benefit of what you have here and some of the reasons you put the coolers there.

Hopefully they wont pressurize the "low end" (low pressure) side of the cowling/baffle system.

Another reason for firewall mounted oil coolers is the warm air dumps "down" at the rear cowl opening. Maybe I missed it somewhere and you took care of provision of where that air goes.

Test test test change test! Cant wait to see this plane together!
 
Yes, oil cooler air is routed to rear-facing outlets and forward-facing inlets pressurize cabin heat. We didn't use the Vetterman hangie-downie pipes. With two mufflers I have two heat boxes and two heat-defrost controls. At face value this looks like it should make a toasty cabin. The FI air box is big. This engine won't starve for air.

d00bcbdb3a2808ed5db5742e15697fd5.jpg
7e964803fa8b6d523b3a397342604e0e.jpg



Sent from my iPhone using SuperCub.Org mobile app
 
2. Is the cold oil gonna be congealed when you decide your oil temp needs reduced and you open the doors? maybe!

He’s controlling the air flowing through the coolers, not the oil flowing through the coolers.

With the doors closed he just won’t have any air flowing through the cooler fins to strip the heat from the oil. Some heat will still transfer to the metal cooler and radiate away, but not as much as if air was flowing through the coolers’ fins. So doors closed = hotter oil in the whole system, including in the coolers.



If he was controlling the oil flowing through the coolers with a ball valve then congealing would be a potential issue, since the coolers would always be cooling but the oil wouldn’t be steadily replaced by hot oil. The stagnant oil would continue to cool, potentially down to its congealing point.
 
Dave’s comment has merit. Here’s a link about Reiff’s oil cooler heater page. I don’t know if I need to add cooler heaters but I’ll keep my mind open to the idea. I don’t know anyone who’s blown a cooler from cold starting but I do the quick preheat that Reiff warns about. I’d like to know more about how multi-viscosity oils congeal in modern coolers.

http://www.reiffpreheat.com/Oil cooler heater.htm
 
Dave’s comment has merit.

It very well might, except...

I might be taking crazy pills here, but I can’t see how starving the oil coolers of airflow would make them congeal - as long as you’re still circulating oil through them, closing your oil cooler air exit doors would reduce the chance to congeal, not increase it.

But maybe I’m thinking about a different part of the operation. I’m thinking of steady state flight in extreme cold temperatures. I haven’t given extreme cold starts any thought. Is that what you’re talking about?
 
In a past life flying Beech 18s with R-985s on them, I was taught to religiously use the "oil cooler bypass" for cold starting. They had a bypass valve that could be opened to start the engine. After warm up, the valve was partially closed to start the flow of warm oil through the oil cooler while still allowing oil to bypass if the cooler was blocked with congealed oil. Only when a temp rise was indicated (taken at a probe downstream of the oil cooler) was the bypass valve fully closed. The boss was insistent that we use this technique as he had experienced ruptured oil coolers in the past from cold starts.

Of course, adding a bypass valve would add weight and complexity to the system. If you are able to consistently preheat, or if your oil coolers are stronger than those on an old R-985 and can take a lump of cold oil being pressed through them, it may not be worth the trade off. Using multi-viscosity oil might solve the problem as well.
 
I’ve seen how thick Phillips XC can get in sub-zero temperatures. Radial oil would be worse. My engine has a Vernatherm so bypass may occur until the plane is in flight. I’m not familiar with any local cooler failures from congealed oil but can imagine that two coolers in series may increase the risk when using very efficient direct contact engine preheat that ignores the coolers. But maybe it’s just my imagination.... runnin away with me? In the big scheme of things a couple of hundred dollars for Reiff pads is an insignificant expense, if I decide they’re warranted.
 
As far as congealing, I think you have it handled. My thinking was askew.

My bet is that preheat will get to the coolers as well as the rest of the engine.

My Reiff Turbo in the 180 will over night heat up the cowl sheet metal to HOT, like I pull my hand away instinctively after slipping it inside the engine cover to check it. My cht,egt, carb, and oil temps will be about 115F!!!

Shorter preheat times, maybe some oil cooler pads are indicated for you.
 
I’ve seen how thick Phillips XC can get in sub-zero temperatures. Radial oil would be worse. My engine has a Vernatherm so bypass may occur until the plane is in flight. I’m not familiar with any local cooler failures from congealed oil but can imagine that two coolers in series may increase the risk when using very efficient direct contact engine preheat that ignores the coolers. But maybe it’s just my imagination.... runnin away with me? In the big scheme of things a couple of hundred dollars for Reiff pads is an insignificant expense, if I decide they’re warranted.

I put the Reiff oil heater pads on 79H and 53M based on at least 3 failures I can remember hearing about from cold oil congealing. All were similar in that it was real cold -30 or more, and for whatever the reasons preheat had to be minimized (got to get out of here fast). I do a bit of the deep cold flying for Irondog/Iditasport/Iditarod where I need to go at -40 to get down trail. Generally like a 2 hour run on Reiff preheat as a minimum and the 75 watt oil cooler pads are just 75 more watts directed to a place that takes a lot to heat up as the oil coolers have close to a quart in them. I shudder thinking of a glob of cold soaked 20-50 trying to find its way out of the cooler and into the oil journals of a running engine even at idle warming up. Like you said, for the cost I think it’s rational protection of the critically needed and expensive engine.


Sent from my iPad using Tapatalk
 
if you are worried that your oil cooler is to cold from a 2 hour pre heat, then you shouldn't be going yet...

in 2 hours the heat has not traveled to get the crank warm, and get the hydraulic lifters unglued.. and you will probably knock chunks of the lifter faces and cam as it hammers them and stumbles warming up till they come unglued and fill up....
 
A couple if hours with a Reiff turbo XP package is more than enough to warm an engine from the low teens. In that time would any heat make it to my nose-mounted coolers? I'll find out, but low teens won't congeal the oil. On a -40* morning? I might feel better having cooler heaters. I'd feel even better if I was somewhere else! ;)
 
Last edited:
I would think from my experience that having a good engine and prop cover and a fan of sorts to circulate the source of preheat most anything in the engine compartment would get warm. If someone is concerned then place the remote probe from a battery indoor/outdoor thermometer in there. Leave the display in the cockpit is what I did on one plane to see how miserable I was until it warmed up compared to the engine.

Gary
 
Very nice plane. Local mechanic used to take out his pocket knife after a fresh cover was barely dry and ask "let's get this over with now...where do you want the first hole?"

Gary
 
Looking great as always!

I enjoy the oil cooler discussion. I have limited experience with the Reiff and Tanis type heaters, but what I have seen from the times I used them is that with a reasonable set of insulated covers you will heat the entire engine compartment enough to at least bring temperatures up on all parts inside by the time the engine gets heated throughout.

I don't see where the oil coolers would remain so cold as would be congealed by the time you want to start the rest of the engine. You don't need that oil up to full on temps, but if it is even up to 30 degrees it will cycle out through the system and mix, allowing it to warm.

As MCS Mike said, if the oil in the coolers is cold enough to be a congeal issue, the rest of the engine is not ready to fire off.
 
At -35 the Reiff does a good job on sump and cylinders but these coolers are separated from the engine so no heat share. I don't have plans to fly at -35 anymore so that's a bigger factor in my decision than anything.
 
At -35 the Reiff does a good job on sump and cylinders but these coolers are separated from the engine so no heat share. I don't have plans to fly at -35 anymore so that's a bigger factor in my decision than anything.

Doesn't the Reiff heat the ambient air inside the cowl? It is that ambient heat that would bring the coolers up from the outside really cold to a more moderate temp.
 
Usually not in the amount of time I use a preheater. I use Reiff because it's fast and efficient. It puts heat right where I need it (except maybe the oil coolers :) ). If I left it on all night would it warm the coolers? Probably a little, but I usually don't run it for more than 2-3 hours even when it's really cold (I use a generator). Once the engine temp reaches 20* I'm good to go. By that time I'm anxious to go. Given my preheat routine I wouldn't count on any heat reaching those oil coolers. It's a little like using a remote oil filter, which my mechanics don't like. An engine-mounted filter gets some preheat from the engine. Remote filters don't. That's changed in the past 20 years since the days we all blew hot air into our cowls. I've never had remote oil coolers before. Maybe adding heat pads makes sense. After all, the goal is to put the most heat my 1000w gennie can produce into the engine as quickly as possible.
 
Last edited:
Doesn't the Reiff heat the ambient air inside the cowl? It is that ambient heat that would bring the coolers up from the outside really cold to a more moderate temp.
George,

Of course it does. As it heats the metal it is in contact with but if it’s really cold it takes awhile. I have the high output (Reiff Turbo-XP system 100W/cylinder and 200W on the sump) on my 180. That’s a whopping 800 watts (that’s less than your wife’s hair dryer) to heat a 300+ pound chunk of metal, 2-1/2 gallons of oil and then heat 20-25 cubic feet of air in the cowling to transfer that warmth to the cooler. From my experiences when parked on a ramp overnight at zero-ish with a really tight fitting (one of those skinny-jeans style) cowl cover and only generator power available in the morning to pre-heat it took about 2.5 hours to get to 80 degree oil (cylinder temps were 100-ish) and I’d guess the oil in the cooler was maybe 50-60 (the cooler wasn’t warm to touch but wasn’t cold either). On start up I saw an immediate oil temp dip of 6 degrees as the slug of oil in the cooler and lines went through but you had to be watching a digital gauge to see it (Stewart told me to) because it stabilized really quick. Had I had anouther hour, I’m confident I would have seen 90-100 degree oil, 150 degree cylinders, warm cooler for less dip on start up.

That said, equating that to 30 below, I’m afraid I would be calling you from Florida to come refill the generator for a second pre-heat run and tell me how great Alaska winters are...

Kirby

Ps. I’m not sure if I’ll have to do any cold opps this winter or not but I’m going to add a cooler heater element just in case.
 
Last edited:
Warm insulated cowl cover is the only way to go.

Stewart, your intended purpose, gen set for two hours, makes a difference. Working we just plugged in at the end of the day and left if for the night. Different situations, which is why it is a great discussion.

As well as you have thought this bird out, I am excited to hear the first year report on how it all turns out.
 
We all have our conditions that we operate in. Sometimes we forget we aren't the only ones operating. Lord knows that applies to me!

The Wildcat is shaping up to be a VERY cool airplane. Every night I close my eyes and dream about the first flight. I'm 98% percent finished. Only 40% left to go! F--k I hate airplane math!!!
 
Back
Top