I dont agree on having to change AOA of throttle. What is really needed is to understand that Groundspeed will increase during base leg on the wind conditions above. The pilot will need to either do the downwind leg farther from the centerline, or need to carry the necessary throttle and speed for a tighter turn than expected. Otherwise, will miss the runway

But none of that has anything to do with AOA and throttle settings regarding airspeed. It is all about keeping the airplane inside the fixed box we want it to be, even if the air where it flies is moving...

Gents,
Sounds like there's an agreement here. The issue is that most RC model pilots are not full scale pilots, so some concepts written by full scale pilots need to be sometimes over-simplified to be easier to understand for those that haven't "felt" wind or compared ground speed to indictated air speed.

The "best" way to tell "indicated" airspeed with an RC model (IMHO) is by angle of attack in level flight for a given configuration (flaps up, gear up, or flaps down gear down).

A great way to teach this concept is to have an RC pilot learn how to fly a perfectly round circle, level, at a constant perceived speed in moderate winds. By starting into the wind at about 3/4 throttle, flaps up and gear up, the circle can be flown level and round by adjusting the throttle and bank angle. Downwind throttle might be as low as 1/2 throttle to keep the speed constant, but it should still be well above the stall...notice the the angle of attack (AOA) will be higher, more up elevator (trim) in for level flight.

Flying this circle several times should cement this into a willing student's mind, at a safe altitude and well above the stall. This lesson should translate well to the traffic pattern where it is much more critical.

Goal: When flying the same level circle leaving the throttle fixed at 1/2 (or 3/4) with the same model and configuration a person can see the difference in perceived speed (speed relative to the ground), with "indicated" airspeed (and angle of attack) remaining constant.

Who else has jet training syllabi or recommendations?

Over 50 flights on a high performance aircraft capable of over 100 miles per hour was a good highlight, though it was included in the original post by Jeremy and the AMA regulations linked in my post...I added an "assumptions" line in front of my draft training syllabus. Can we assume that everyone has read the AMA turbine regulations and waiver program???

Nope! Since you have agreed that the plane flies relative to the air, why would you alter the throttle? And when turning, at some speed and angle of bank there is one and only one correct amount to pull back on the elevator. Any more results in the nose rising and a climb and loss of speed, any less results in the nose dropping and height being lost and an increase in speed. Ignore the wind, you fly the plane to the same throttle, speed, angle of bank and AoA as you always do. If a cross wind is blowing you towards the runway you start the turn on to final approach early to allow for the drift. You use the same throttle, bank, speed, pull etc as you always do.

Harry C, Jack and All,
I researched this and the discussion regarding landing jets originated from Steve Ellzey's article in the Summer 2008 issue of "Contrails", Vol.18, Issue 3, Page 5. Steve discusses landing techniques as derived from 2 Top Gun class competitors for the various landing legs including upwind gear pass, downwind leg, turn- to -base, approach and flare to include compensation for wind. This is where the confusion begins and I suggest thatthe guidedelete all discussion regarding wind compenation as this can be bestexplained in actual practise.
I do agree that wind effects must be compensated for in landing and thatthe model airspeed remains constant for a given throttle setting and AOA- with no induced bank angle.Differences in ground speed may be perceivedby the pilot standing in a fixed position and this may lead to landing problems.
Thanks to Harry C and Jack D for bringing this to attention.

Art ARRO

There are experienced professionals who have written articles that just don't come across the way they intended...another good reason not to take everything we read at face value with out applying mixing in a little real life experience and trying things out for ourselves. Reality often strikes at the strangest times.

Flying a figure 8 is even better, one circle into wind the other is down wind if that doesn't give a clear indication to the pilot nothing will.

Mike

Two videos by RC Jet International magazine and Ali Machinchi that bring up some very good points about turbine jet flying. First a basic overview, then one about flying more than "circles."

Preview of "Beyond the Circuit" here: http://youtu.be/tlFEcDVAqqA

Link to buy videos:

Europe - https://www.google.com/url?sa=t&rct=...41248874,d.d2k

Ebay might have a deal on these videos as a package deal.

Maybe these videos can help someone else like they are helping me!

A little proficiency training for RC jet pilots who want a challenge...the new season could bring a little F3S flying to the U.S. for those of us that are interested in stepping it up a notch.

Looks a lot like the IMAC Sportsman sequence, I wonder how many jet pilots could fly the whole sequence in one tank of fuel? Might be fun to challenge each other at a jet meet some time for a little "friendly competition." [8D]

I see a lot of people having success using this reasonably priced trainer jet called the "Tornado." It is an ARF made by Modellbau with carbon fiber spars and carbon fiber reinforced booms...designed for turbines, not a wooden pusher-conversion. Composite fuselage and CF reinforced balsa wings and booms/tail section.

If you know and like TBM: http://www.troybuiltmodels.com/items/MBATORNADO.html

This trainer jet, along with all the gear to outfit it, costs in the neighborhood of $4000 RTF if you buy everything new.

Turbines: http://www.troybuiltmodels.com/items/K-80E.html

Landing Gear System: http://dreamworksrc.com/catalog/mode...bo-p-2533.html

The reason I chose to post these links was a common retailer with a lot of parts and competitive pricing...TBM...and a trainer jet that is being produced that you're likely to get a ton of support on the forums for...since you probably don't have a lot of jet pilots nearby. Being able to get help on a like aircraft and turbine is extremely valuable when getting started.

Use the "Search this thread" option after clicking on this link to get info on this Tornado Sport Jet: http://www.rcuniverse.com/forum/m_10095724/tm.htm

This aircraft will go fast if you leave the power on, but will slow down to a crawl for landing. Believe it or not, this price is extremely competitive...the turbine itself and landing gear really don't go down in price when you buy a more expensive airframe.

I am not affiliated in any way with TBM or Dreamworks, though I've bought their products in the past. This is AN option...there are many more.

Anyone have another idea with some links and pics?

I've been hearing a lot about trainer jets lately...some people just don't like "twin boom" jets...so here are some alternatives:

EXM Sport Jet, all wood construction, built like a modern 3D plane and it can the stress of high Gs. Nice thing about this one is that a smaller turbine can be used since it is light for its size.

Shulman Aviation Turbinator, all wood construction with purpose made gear mounts that are a little stronger for grass and the occasional harder landing. Also can use a wide range of turbine sizes.

Futura, all composite sport jet with light wing loading. This plane flies like a pattern ship and is has a large frontal area on purpose to take advantage of the drag to keep a constant speed during aerobatics.

All these jets slow to a walk for landing and can be flown with 1/4 throttle on final with the flaps down to minimize spool up time for a go around. Even more drag can be generated with the use of "crow" (up ailerons) if a higher power setting is desired on final and into the flare.

A Feibao Velox is a good jet trainer as well and it will be a rocket if you go at WOT. ;-)

Looking for a good first jet?

380 bucks, builds quick, simple configuration, looks good, flies slow, doesn't need expensive servos or powerboxes, flies on a small turbine.

Give some serious thought to the Mick Reeves Super Reaper. Just put some sort of drag device on it. It's easy to do. Just look at the pictures in this thread.

Here's the thread with a link to his website: http://www.rcuniverse.com/forum/m_11431284/tm.htm

[/quote]
Harry,

We've been down this road before,with the ''downwind turn myth'' thread. You saying it's all nonsense,is nonsense. Your statement ''Wind has no effect on airspeed in a turn, and changes in groundspeed have no effect on handling'',while tehnically true,is overly simplistic,and misleading.

The intent is to make the newbie aware that visually perceived speed will change significantly,at a constant airspeed,when changing course in a strong wind.That is a huge point. If he flies the airplane at a comfortable buffer above stall speed into a 20 kt headwind,then turns downwind,the groundspeed,and more importantly perceived speed, will be 40 kts faster,if he doesn't change pitch/power. An inexperienced pilot may incorrectly perceive that the airspeed is increasing,and make the improper input of decreasing power/increasing pitch,leading to a stall,and departure from controlled flight.I have seen it happen more than once.

You,and others have argued the semantics of this,yet it continues to be a problem for newer pilots.It may not be explained exactly correctly on the JPO sight,but at least the attempt is being made to enlighten newbies that there are extra considerations when operating in stronger winds.I applaud that effort.

Erik


[/quote]

The effect is even worse in very gusty or variable winds. Le'ts say your model jet stalls at 30kts. You are on final approach into a 15 knot wind. You are flying to maintain what appears to be 35kts across the ground. Your actual airspeed at that point is 20kts. If the wind suddenly quits or makes a drastic change in direction, your airspeed, at that split second, is now 20kts and you stall. Full size airliners always add a buffer on the Vref speed precisely for this reason. On the Airbus, the computers do it automatically. On the 757, you add 1/2 the steady state wind and all the gust factor to your Vref (approach speed). With model airplanes we have to do all this by eye.

With model airplanes, because we are not sitting in the pointy end with airspeed indicators, this problem can be insidious. Let's say you are flying your model jet on downwind and the wind at that altitude is 20kts on the tail. You are flying the model at what appears to be the proper speed, yet in reality the true airspeed is 20kts less. You turn base and final, and for a brief moment, until the momentum of the airplane catches up, you are flying at your actual airspeed, which may very possibly be below stall speed! Since we usually start a descent at that point, I suspect many a stall has been averted for that reason.

Dustflyer,
You sound like you've seen this before...but might be worth being very clear when you are talking about "ground speed" vs "air speed." Two very different things.

Al

Al,

Gee, I thought that was clear as mud, but then again it always sounds perfectly clear to the guy who is writing it! Let me see if I can muck it up a bit more. Seriously, let me take one more shot at this.

Groundspeed is airspeed plus or minus the wind. Airspeed is the actual speed of the relative wind over the airplane. 40kts airspeed with a 20kt headwind equals a 20kt groundspeed. 40kts airspeed with a 20kt tailwind equals a 60kt groundspeed. In both cases, your airspeed is still 40kts.

It's all very easy to understand as long as you are dealing with a steady state wind. When the wind gets gusty or rapidly changes direction, the dynamics change. In that case, indicated airspeed can fluctuate greatly with no change in power.

The first issue deals with aircraft momentum or lack thereof. It you have 40kts of airspeed in 20kts of steady state headwind and the headwind suddenly stops, what happens? Is your airspeed still 40kts? No! Believe it or not it's 20kts! This confusing little issue has been the cause of a number of windshear crashes before the phenomenon was understood. Let's say an airliner is on final at 130kts and flies into a downburst. These typically hit the ground and fan out, so if you fly into one you get hit with an instantaneous headwind, followed by a horrific downdraft, and then a huge tailwind. So let's say an airliner is initially hit with an instantaneous headwind of 50kts. The pilot will see an instantaneous increase of 50kts on his airspeed indicator. He pulls back the power to maintain approach speed. Next, he hits the core of the downburst then rapidly enters a 50kt tailwind, which results in an instantaneous decrease in indicated airspeed of 50kts. So there's the airliner, thrust pulled way back to maintain 130kts, while his groundspeed is actually 80 knots and he's getting pushed into the ground by a downdraft. Next, he gets hit with an instantaneous decrease in indicated airspeed of 50kts. In that scenario there is no chance of recovery. A crash is inevitable. That's why airliners use wind additives on their approach speed, so the airplane will have enough momentum to deal with the airspeed fluctuations. Nowadays, of course, thunderstorms and downbursts are avoided, and it is a typical policy to abort the approach if airspeed fluctuates by more than plus or minus 15kts below 1,000 feet.


The second problem deals specifically with model airplanes. How do we judge airspeed? By eye. By observing how fast the airplane is moving. But relative to what? The ground! We fly by groundspeed because that is all we have to work with. So we fly by "perceived" airspeed. Here is were the problem lies, and as Erik has said, it has claimed many a model airplane! Let's say our model stalls at 30kts and we are flying into a 20kt headwind. A normal approach speed would be stall speed times 1.3, or about 39kts. We fly our model at what LOOKS LIKE 39kts to us. Now lets say we suddenly lose that 20kt headwind, our airspeed will instantaneously drop to 19kts! So based on the concept of "perceived airspeed" we kind of have to make a little adjustment in our heads. If we adjust our throttle setting to maintain a constants perceived airspeed in gusty situations, we are actually adjusting our actual airspeed without knowing it! This problem manifests itself in the worse way under three situations; the turn to downwind, the turn to final, and final approach under gusty wind conditions.

Granted, this is all a bit much for an RC flyer to keep in his head. The bottom line is to remember we fly model airplanes based on perceived airspeed, not actual indicated airspeed. The actual airspeed of the airplane may be faster or slower than it appears. Be cautious going from headwinds to tailwinds. Keep in mind the airplane cannot make instantaneous changes in actual airspeed to account for sudden fluctuations in wind.

Many modelers judge the airspeed of their model by guessing...throttle setting is only one piece of the "airspeed" equation. Configuration and angle of attack complete the picture.

IMHO, the best judge of airspeed is by knowing the aircraft angle of attack for a given throttle setting and configuration at stall speed, then keeping the angle of attack less than that to remain above stall speed. The only way an RC turbine pilot can discover this is to run the aircraft through a series of stalls at altitude. Overly mushy controls are also a good indication of impending stall for many jets.

Knowingly flying at a higher airspeed to maintain a familiar ground track will keep an aircraft safe when experiencing gusting headwinds. For steady state headwinds it is still a good practice to fly a little faster airspeed and make the approach and landing look familiar in terms of grounds speed and track. A short, steep approach with a lot of headwind can result in disorientation when it comes to the flare and touchdown. The increased airspeed on a calm day would take up a lot of runway, but with a stiff headwind the landing can look fairly normal with an average roll out distance. The higher throttle setting will be convenient if a go-around is necessary, since there will be little turbine lag.

Watching angle of attack of the aircraft on the "downwind" part of the pattern will help avoid stalling, specifically with flaps at approach and gear down. The groundspeed will be higher than what looks "normal" due to the stiff tailwind, but trust the angle of attack for this configuration (memorized from a calm day) to judge the airspeed. Resist the urge to pull the power back further than usual on downwind.

With crosswinds in the face, making a pattern slightly wider than normal will allow spacing to keep the aircraft on speed (angle of attack) and avoid the dreaded "base leg stall" when banking up for the final turn. No better way to make the flightline Safety Officer nervous than an overshooting final with an RC turbine headed toward the pit area while it is getting slow and on the verge of tip stalling. Less bank and under complete control to touchdown will inspire your local Safety Officer to ask you for landing advice.

Updated RC Turbine Checklist for your consideration. Feel free to use it to make your own checklist, take it as is, or disregard. I'm still interested to see if anyone else has a checklist they use as a training aid for new turbine pilots. As a volunteer RC instructor pilot this checklist will help me give students a repeatable standard born from recommendations by those in this hobby we look up to.

Just like with full scale jets, a checklist is a good way to make sure everything important is briefed to the crew and completed on time. If we fly at an AMA approved flying site as part of an AMA chartered club we are required to use a spotter while flying RC turbines...so the two of us are a crew at that point.

Our increasingly critical political environment, in general and in our clubs, will require more vigilence. How our club members perceive us as jet pilots is almost as important as how safe we really are.

Your thoughts? What do you use as "memory joggers" to safely operate your turbine models?

Jet stick planes are the next step in club proficiency...practicing a flight before performing it will help people visualize maneuvers and remove ambiguity. I got these from Callie's Graphics. She prints vinyl that matches your jet exactly, if you want. She can also do some generic schemes (www.callie-graphics.com).

***Updated RC Turbine Checklist*** to incorporate Sparhawk's recommendation...RX off first, then TX. If your system requires something different, modify the checklist for your needs. Thanks Sparhawk!

Albert,
Really great thread developing here, especially for the noobie jet pilots. I printed off a copy of your checklist to show at my local R/C club meeting tonight. This club has a current ban on turbines and I'm trying todemonstrate oursafety awareness to get the ban lifted.
I also recommend having your RCTurbine Aircraft Checklist posted on the JPOwebsite (www. jetpilots.org) as a document. Just contact Keith S., JPOPrez, to get this accomplished.
Again, many thanks on compiling this checklist and to all that contributed to this thread. This is what the RCJets forum should be about.

Art ARRO

I too use a checklist, it is printed and laminated and sits on the ground in front of me as I prep a jet for flight. I use it every time, start at item 1 and work my way through. Things like fuel valve to closed before fuelling, all aerials in place, batteries load tested, overflow tank attached, fuel filler bung replaced before start up, all air systems pumped up, etc etc. Then I follow the BMFA suggested process for the Tx of SMMART - Switch Tx on, Meter (battery meter ok), Model (correct model memory selected), Aerial (not such an issue now with 2.4Ghz but a check that the LED's on my Weatronic and Multiplex modules are showing correct blink codes), Rates (rates switches etc to correct position) and finally Trims not such an issue now with digi trims but my fav old tx has mechanical trims so it's still valid. Finally to the model I count 4 items - Battery 1 on, battery 2 on, turbine battery connected, manual fuel valve open.
By following the routine of printed lists and memory pnemonics like SMMART I am always confident that everything is ready.

Art ARRO, precisely the reason the jet guys need to step up and lead...being safer and more disciplined, so no one needs to question the preparedness of the turbine pilot...nor the proficiency.

HarryC, I like your technique. Using something that is easy to remember is also a great way to guarantee success. Maybe we can come up with pneumonics for each of the checklists if we work together. Before start, Starting, Before Taxi and Takeoff...not sure if that is doable, but it could improve my checklist by making it easier to memorize. Mine is mainly for those first few times to the field after a winter break, or for getting a club to start thinking more seriously about turbine safety. I'd like to pay more than just lip-service to safety and proficiency.

Gents, I'll send it to Mr. Seivers to see if he's interested in posting it in the Knowledge Wall section of the JPO website. It would be better if there were several choices, and people could even make their own from the samples there.

Who out there is a current turbine instructor? What tools do you use to teach...or do we do any teaching at the advanced pilot training level? I'm batting around the idea of putting on a full day "Turbine Training Clinic" for free out in Northern California in the Spring of 2014. Maybe have a small landing fee that covers lunch.

This will be a purpose driven get-together for learning at all levels...from just getting new people airborne, to getting people through their turbine waiver check and working with some of the more advanced turbine pilots in the area to demonstrate and teach good techniques for high energy flying, good airspeed management and overall proficiency flying high performance turbine aircraft. I'm a CD, but people with specific strengths to teach different parts of the Clinic and two or three "roaming helpers" could make this a hit...even if there were only ten turbine pilots that show up.

Ideas?

After HarryC posted his info including the BMFA resource, I went to the site to see how the UK certifies turbine pilots. In the past I've also visited the MAAC site to see how Canada does it.

Check out the Basic "B" class training syllabus below, called the "Radio Control Achievement Scheme." It is a little more thorough than your average club's training program here in the states. The picture is of the first page, the link to the full PDF is here:
http://www.bmfa.org/achievement/2004...ide-Issue1.pdf

How many non-UK turbine pilots could complete the Gas Turbine Achievement Test in the chart below? It is found in a pretty comprehensive document here:
http://www.bmfa.org/achievement/files/2013/C(GT)-2013.pdf

For more in-depth reading, in preparation for a new flying season and to gain more perspective as a safe pilot, check out the BMFA "Code of Practice for Operation of Gas Turbine Model Aircraft:"
http://www.bmfa.org/publications/fil...ssue%202CB.pdf

My goal, to push my flying to a level defined internationally, is to be able to fly the BFMA "C Certificate (Gas Turbine) Checklist" in one flight, with a smooth flow from one maneuver to the next. Anyone else up to the challenge?

How about a link to a video of this being done in less than 10 minutes?

Agreed, this is a good read.
Albert - The one thing in the check list I don't like is in the Post Flight section. You have the Transmitter power being shut off before the receiver power. I NEVER do it that way. Receiver power is shut off only while still in control by the transmitter. 2.4 or FM, this is the way it should always be done. Jets or prop planes makes no difference. I've seen gassers with failsafes not set properly go to full throttle... not fun. With jets if the turbine is off, it may save your flight surfaces in the accidental gear up glitch or other unforeseeable issue. Food for thought.

Dan

Sparhawk,
Good discussion point. Do you leave your transmitter on during the two minute turbine shutdown/cooling sequence?

Please explain how you operate your ECU and turbine shutdown sequence. I appreciate the feedback.

I've seen it done both ways at jet rallies and you bring up a good point. How does the rest of the RCU jet community do it?

AMA requires EVERY RC jet pilot to have their failsafe set to throttle down, trim down...how your control surfaces and gear are set up is up to the individual, though to use this technique the landing gear have to be "down" during failsafe operation.

Note: When a person first turns on most 2.4GHz systems, TX first, then RX, the system will still start with the failsafe condition, then go to the TX selected condition. Better have that gear down selected for the failsafe if you're turing on radio equipment after fueled and sitting in the pit area, with wheels on the ground. I can't imagine leaving my TX on that long, or picking up the jet while I turn on my TX, just in case my failsafe is set incorrectly.

Failsafe set up (throttle) it is part of the AMA basic turbine waiver check requirements and a person must demonstrate this knowledge.

My ECU power is always on when the RX is on...ECU battery is plugged in all day without a separate switch and unplugged at the end of the day. If there is enough of a demand for it, I'll go ahead and finish the "expanded edition" of the checklist which has each step, followed by a short paragraph explaining the step, logic behind it, notes, cautions and warnings that apply to it. The outline draft version includes articles in truncated form from advice I received from experienced RC turbine pilots, BVM, JPO and AMA documents on RC turbine jet landing, maintenance and proficiency training.

Yes, on my gassers, electrics, etc. I always turn off the RX first, then the TX and my failsafes are all set...most events with large models here in the U.S. have people demonstrate failsafe conditions before they are allowed to fly. For ALL RC models, TX on first, then RX...at least for the brands I use. I'm not sure if there is a brand out there that has a different requirement.

The latest JetCat ecu's power themselves off automatically and run cooldown even with rx off, just for info.