Eddie P

My Feedback: (4)

One potential issue with operating on loose, deep snow would be ingesting ice or large amounts that could damage the comprssor blades, etc. You could get a flame out from a lot of snow entering the engine fron your nose leg ski deflecting snow into the itakes or engine, but you'd probably have an idea of what mods you'd have to make to that after a few taxi runs. You just don't want snow depositing in the inlets and then going through the engine in clumps - so keep spray out of the inlets. If you flew around in snow and injested snow and ice formed and came in in clumps you could get 'soft fod' damage too but again why you'd fly in active snow I have no idea. By the way soft fod is not a model engine term it's a full scale engine term when pilots forget to put on the protective anti-ice feature of the engine when operating in these sorts of conditions - ice then forms on the inlets or fan blades, breaks off occasionally and clumps of ice go through the engine. The damage might not be seen right away aside from slightly hotter EGT'S, until the engine goes into overhaul but it's quite expensive to fix.

A slight amount of water vapor or very fine ice crystals going into the inlet, as mentioned earlier, would produce a small increase in thrust as it essentially mimics the old practice of water injection like in the 1960's for the pure turbojets back then were like our model engines today. Makes a lot of steam and moke but it does incrementally increase thrust - the problem is there is not way to plan for it or do it justice in a small model turbine. I don't get the feeling you are looking to carry around a 10 ounce apparatus for a 5 ounce thrust gain for 30 seconds, you are probably just asking if there could be damage.

Other than all that I personally think it can be done safely. It's not like you are flying in a sand storm or ingesting fine rocks. THAT stuff is in fact nasty and fatal to an engine.

FILE IFR

I'm not the kind of guy that's out to ruin a good time and I like seeing variations in the hobby, but I thought the AMA required brakes on all turbine aircraft.
Hey, I'd love to see a ski/float fitted turbine taking off and landing, I wonder if the AMA would 'like' to see it too.

Sorry for drifting off-topic here.

Mike

funflyerf4

My Feedback: (6)

There is a screen on all inlets on the plane and a fod on the turbine.It should be interisting I can't wait.



Frank

Helijet

I have flown a few times in the winter and the turbine / airframes absolutely love the cold, dense air. Sounds very different too. Have flown in some light snowing conditions and of course rain. Don't worry about it - the engine can handle it just fine. Like the guys say - avoid the snow banks and yellow snow and all will be well!


Dean
www.pstna.com
from the cold, presently white North

Eddie P

My Feedback: (4)

Don't confuse us with the FACTS

FILE IFR

LOL, I was afraid of that... Sorry for the confusion here-- And what the hell was I thinking??

NickC5FE

My Feedback: (31)

Fod guards wont protect against ice building up on the compressor. Is it really that cold??

Planker07

A member in our club has a Northstar with a PST turbine that he flies off of water. There is some pics on our web site. www.ercs.ab.ca

siclick33

[ To get intake icing you need cold temperatures and moisture (so don't fly in cloud or fog when it is cold). Snow indicates the low temperature but not necessarily the level of moisture. (As an aside, intake ice is also likely in low positive temperatures in moisture. I have never heard anyone suggesting to stop flying when temp drops to, say, +10C so I don't think it is a concern in our application). After a snow shower the air might actually be quite dry; if it was still actually snowing however this might be an issue. Also there would be the issue of the snow 'blocking' the intake causing higher temperatures and eventually reduced power (as the ECU limits max temp). A third issue of flying whilst it is snowing is obviously the reduced visibility.

If the snow is simply lying on the ground then the problem is really limited to take off and landing; in the air you will be fine. The effect of this might depend on how packed the snow is. If it hard packed then you will probably have little problem.

If it is soft then you need to make sure no (or very little) snow is thrown into the intake. This may cause intake icing during the take off and it may block the intake with snow. In my opinion, however, the biggest problems relate to increased take off run and ground handling difficulty caused by increased friction on the wheels. Obviously if you are going the ski route then this will not be an issue.

I think the issue of FOD damage caused by snow is unlikely. If you have a FOD screen then that will help (although it may be easier for soft snow to block the intake). FOD damage caused by intake ice will only occur when that intake ice breaks away and goes down the engine. It is likely that this would only occur when the engine is heated externally. For instance, one problem area on full size aircraft is when the pilot turns on anti-ice after flying into icing conditions. The ice that has already formed now breaks away and goes through the engine. Other times this could occur is if the aircraft is flown into warmer air or, most likely for models, after the engine had been stopped after flight and the intake temperature returns to normal. This may then FOD the engine during subsequent start.

In summary. If you are sensible and fly when the weather is good then I don't think there will be a problem. If you fly from soft snow and think snow may be ingested into the engine then I would try to find some way of pre-heating it to melt any ice that has formed inside. Finally, have a good check of the FOD screen every flight to make sure it is clear. Otherwise, sounds like fun to me

p.s. This is based on my knowledge of full size snow operations. I haven't flown a jet model in snow and can't give you first hand experience.

Brian B

My Feedback: (5)

Funny to see this old post pop up again after 4 years. I never did fly the Facet off snow, but I still have the plane and we have a LOT of snow here. Unfortunately it is -10F here right now. A bit too cold for me and the RAM, I think.

ytrewq

As regards water ingestion, on the VTOL Harrier they carry 50 gallons (I think) of water which is sprayed into the intake when in hover mode.

Alan

funflyerf4

My Feedback: (6)

Who said there ther was no brakes on the plane?IT still has its wheels andBRAKES on.Ands those are the FACTS.

flyinfool1

My Feedback: (2)

I was not intending to fly during snow, just to fly off of snow.
The snow here is nearly a foot deep so wheels are out of the question.
I do know that once you get them started most engines really like the cold.
Like today where it is 8 F, clear blue sky, with a 5MPH breeze right down the middle of the field.

I just have no idea how big the skis need to be made to support a 22 lb jet on snow.
The R54 gets off the ground pretty quick with the P70 on wheels and I have almost 1000 feet of runway to work with.

I am going to get a set of the Du-Bro skis and scale them up and then I will have them to put on one of my planes with the meat cutter up front. the 3D ships are easy to hand launch but skies might be fun.

FILE IFR

Calm down and relax yourself Frank...It's already over with[sm=spinnyeyes.gif]

My question was not really a serious one. Seeing a plane without effective brakes for snow ops. doesn't keep me up at night.

Woketman

My Feedback: (6)

I wish I had to worry about skis down here! It is about 75 degrees out and humid. It has gotten down to 38 deg. one night last week, but that's rare. And during the day it is still getting hot. I am so tired of hot & humid!!!!

icepilot

Hi guys!

Here in Norway we regularly fly during winter - and I mean WINTER - with down to -18 degrees C, and we have no problem at
all starting or running our turbines. We keep the gas warmed up in a car or under the down jackets, and the only problem the
cold gives us is the gear which will malfunction unless you fill a little anti-freeze in the air system. We do get better thrust in the
cold air, and I have personally had my turbines ingest snow many times landing on the ice, and there was no effect on the
turbine.

As for getting any extra effect/thrust out of the turbine, one fellow Norwegian jet pilot named Malones tested water ingestion
in his turbine quite extensively, and there was no increase in thrust and no other noticable effect.

On my small SU27 the turbine is mounted between the original turbine shrouds, and as you can see, snow is being thrown up
on landing as well as take-off - no problem!

Tor

PS: -18C equals 0 Farenheit

SKY HOBBY

My Feedback: (1)

Brian, if you remember my MB 339 on skies, we were having problems with flame outs during taxi. As it turned out the nose ski would throw up just enough snow to get sucked in and cause a flame out. i taped off the bottom portion of the inlets and that took care of the problem. Never did any damage to the engine, but would cause flame outs. I would think you should be fine with the engine position on the facet. Dave

flyinfool1

My Feedback: (2)

It is good to know that the turbine will be fine in the snow.
Are you running Jet A1 or kero in the cold?

We do not have a hard frozen surface to work with so I still need to figure out what to use for skis.

icepilot

Most of us are running kero. I would use the same material for skis that we use
for large prop planes - aluminum with an angled "tunnel" on top to make it strong
enough and a spring system to keep the skis angled slightly up in front when airborne.

shogunmst

My Feedback: (3)

I cant imagine that sucking in snow could be a good thing, very little OK, but even with full scale turbine engines we are always worried about the formation of ice FOD, I bet that these small scale versions are vulnerable to this also. Just my opinion though, wouldn't want to find out with the price of turbines so high. Good Luck

bidrseed2

My Feedback: (2)

Regarding getting fan blade icing, the rules for full size, are that the temp has to be below 10c and less than 1500m visibility before engine icing is a consideration.

We might fly models at less than 10c but wed never want to fly when the visibility was anywhere near 1500m.

(The above only relates to compressor/engine icing from the air and not from ground deposits)

flyinfool1

My Feedback: (2)

OK, So here is the plan.

I am going to take a 12 inch square piece of plywood and place it on the snow that we have now which is a light fluffy snow about 10-12 inches deep. Worst case scenario.
I will weigh the wood and then add weight to see how many pounds per square foot the snow will hold till it sinks 2 inches.
From this I can estimate how much ski area I need to hold up my 22 lb R54. I will then assume an 18 lb landing weight at 2 Gs max impact force. (No one make a perfect 1.01G landing every time)

Then I need to decide if that amount of area looks feasible to fly around with hanging off the bottom of the wing.

I plan to make the skis by laminating 4 layers of 1/16 aircraft ply in a wood mold to get the front curve. I will then add a plywood backbone to stiffen it and give a place for the axle.
The bottom will have a metal runner to help tracking and it will be sharpened for those ice patches showing thru the snow. The bottom of the ski will be glassed to help wear resistance.

If this works I will post the plans.

I have nothing with skis right now so all I can fly is my helies where all I need is a picnic table sized area to land and take off from.

L Turner

My Feedback: (3)

Suggested the "FACETSKI" to Kerry Sterner a few years ago: he was not too hot on the idea.

Thought some prefab metal skies, like at http://hometown.aol.com/maidenusammp.../business.html, with good solid connections to the mains and NG axels might work.

Flew my R500 FACET 1200 (wheeled) off the Fond du Lac grass field one fine Jan 1st without much problem. Have to keep the propane warm to get it going, about 30 degrees flaps and off she went. The surface was about 50% frozen grass, occasional patches of low hard crusted snow which it just skimmed, slipped & rolled over. The RAM worked fine in the cold, a great hand warmer which everyone else in the Polar bear club enjoyed! Wouldn't try it off powder.

Looks like the guys in Norway have got the right idea flying off frozen lakes from a plowed ice air strip!

flyinfool1

My Feedback: (2)

I checked out those metal skis, the biggest ones are for 10-18 lbs.
My r%$ is 19 lbs landing weight and 22 with full fuel.
I have sent him an email to see if he can make me a set to handle this weight.
Or I might just get a set to modify for more area.

The more I think about this the more I want to do it.......SOON.

Tom Antlfinger

My Feedback: (24)

Jeff:

Been flying props off snow with ski's for years......best source for ski's is Bill Kvindlog, over at Kvindlog Hobbies in Waldo on Highway 57......he makes beautiful Lexan Ski's in any size you want, and cheap....One of our club members, John Fryman has made some very nice aluminum ones as well...

Dave Elsinger and I had discussed putting them on our HotSpots back about 5 years ago, but gave up the idea after we had seen just too many of our proppers flip over....could lead to a very expensive FOD job and cracked glass on the jet at those low temps......so we kept them on our Something Extras and had a ball.....

Flying off the ice is great....we used to do it off the pond in Dave's back yard at his previous home.....had a hoot and never put a plane thru his kitchen window....

One thing to be careful about is Li chemistry batteries......they are very temp sensitive below 32 F.......at 4 F like last Saturday morning when Dave was out flying his propper Northstar off the snow at the FDL field, Liths could be dangerously low on deliverable power.....Nicads are safer at much lower temps.....

The best way to fly in winter around here is join the Sheboygan club where they have plowed asphalt runways, 750 ft N/S and E/W and Brian French's heated box.....Brian and his buddies fly jets 12 months of the year in comfort.....

Tom