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airbrakes


Jet A

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newbie here.

 

Just wonding if the mark IV has airbrakes...if not how hard would they be?

 

Was thinking hydraulic actuator, airbrakes attached backside of strakes, by the fuselage.

 

Bad idea, good idea, read the plans, already there?

Let me have it.

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Jet, welcome! That's a cool conceptual design, but as Wayne has already pointed out, a brake is already there. Its design is simple and easier to build that what you're proposing.

 

Also, one thing I consider now when thinking about mods is the resale value. However improved (not admitting here that your concept would be an improvment :) ), the design would still be different and foreign to the potential market with no basis of reference. As a result, your "better" design might become worth less than "stock" Cozys.

 

HTH

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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Jet A;

 

Just to clarify;

 

The "air brake" really isn't an air brake or a speed brake.

 

On many high speed military aircraft, Air brakes or Speed brakes can be deployed at any speed, (These are often deployed automatically when the speed approaches Vne/Mne). They are also deployed on landing to add stability and drag, thus allowing the pilot to keep the T2 RPMs up, so a lengthy turbine spoolup won't be required if the pilot needs power , NOW, i.e. go around.

 

The "Landing Brake" on the EZ can only be deployed at the lower end of the speed envelope. Because the EZs airframe is so clean, a normal approach angle cannot be achieved without "dirting up" the clean airframe, i.e. deploy the "Landing Brake".

 

Because of the brake panels physical size and rigging, the manual plans "Landing Brake" is almost impossible to deploy at speeds greater than 120 - 130 kts. (air loads against the brake panel are very heavy). Many builders (including myself) have replaced the original manual actuator with an electric actuator.

 

The original manual actuator would "whack your arm" as it slammed closed when you exceeded its operational speed limit. (OUCH). HOWEVER, the Electric actuators have the ability to deploy the landing brake, at any speed, even exceeding the design limits of the landing brake. They also stay deployed (no "whacking closed"). USE CAUTION, I seem to recall an incident that the panel was ripped from the airframe.

 

I've added logic in my landing gear controller to automatically retract the landing brake whenever the throttle is placed in the FULL position. I also added logic to retract the landing brake if the landing gear "EMER RETRACT" switch is energized.

 

NOTE: I am retrofitting my EZ to full retracts. So, when the gear is down, there won't be a need to "dirty up" the plane for the approach. I've been considering reducing the physical dimensions of the plans "Landing Brake" panel so I can safely deploy it at any speed, all the way out to 1.2 x Vne (260KIAS). I added an electric actuator to my existing landing brake, so I should have enough power to deploy the panel. I'll keep you posted if I decide to do this.

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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Well thanks guys.

 

to anwsers a few of the comments...

I have no desire to sell my cozy, to many lawsuit possiblites.

Second i will be putting in a jet engine (t58 )and keeping it above idle on approach is optimal. That is good info on the landing brake, electric or hydraulic for me. here are some pics where my ideas orginated.

 

Posted Image

Posted Image

Posted Image

 

next question for wayne. how are both rudders applied...opposite directions? is there no mechanical linkage to keep them going the same direction?? or do they only operate one way, and when you apply both you get drag, with no turn? <---- new to aircrafts.....

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EXCELLENT,

 

Don't worry about the plans "Landing brake", its not what your after.

 

I would do exactly what is shown in the photos, and do it with hydraulics. Also, I would have an accumulator that is capable of deploying/retracting the air brakes in one or two seconds. When you need energy now you don't want to wait 10 seconds for the board to retract while the turbine is spooling up.

 

I don't know what the spool up time is for the T58, but this is exactly the reason they are installed.

 

For a turbine installation, you need to be able to get the board in and out fast.

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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What design problems am i going to runinto with these? Obviously both of them will need to come out equal, with both sides. that is easly done with hydrualic flow valves. i like the accumulator idea. Should not be any problem with the brakes coming in quickly due to air pressure, but out will be another story. i would like to have a switch that allows them to come up about 1/2 of the way, and then another toggle that will adjust them down or up for the given situation. this will allow me to fine tune on the ground and in the air.

 

Anybody see any structural issues with this? looks maybe like that paticular design will cut into fuel area, or baggage area?, what about the strakes taking this load? as close as this is to the fuselage, i do forsee any problems with loading but i like to hear others thoughts.

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From viewing the photos, it would appear that many of these problems have been solved.

 

 

The speed brakes in the photo seem to occupy area that is normally in the engine compartment. I would bet that they are mechanically attached somehow to the engine mount extrusions, probably part of the engine mount modifications. Structurally, this would be a good choice.

 

I would talk to the folks that built/own the plane in the photos.

 

As for rudders, they are not connected, you can deploy both simultaneously. These are not real effective speedbrakes, as they are hard to deploy at higher speeds. I also get a significant pitch up when I deploy both simultaneously.

 

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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Waiter, you rock. that website is lots of good info. thanks for that, gives me some more questions to ask some more people that have more familiarity with this. Is there anybody on this forum that is considering this conversion...jet engine?

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  • 2 weeks later...

So what's the advantage of the turbine? (...besides the fact that it is very, very cool.) None of the stats in EZJet's FAQ section point to any great performance advantages over a reciprocating engine, however the price tag is relatively high and the maintenance & operating costs must be up there too.

 

Joe

Joe

Cozy Mk IV #1550

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Richard, while i respect your opinion, may i ask why you do not care for the turbine engine in this plane? you obviously made a point to mention it, and i would love to hear why.

 

Advantages of a turbine engine?

Ranked from most important

1. It is VERY VERY cool! (i am still a kid thats important)

2. Its sounds VERY VERY cool! (see above)

3. In the event of a mechanical failure ie. motor cuts out. you have a slightly better glide ratio due to no prop. Probably not much, but still an advantage.

4. I have an obsession with jet engines. I have built 2. the kind were you take a turbocharger off a diesel and make a jet engine out of it.

5. I have considered the costs of these engines. they are not much more than some of the rotarys that go in these.

6. there is less axuillary parts...these engines need fuel and air. less things to go wrong. I personally believe that turbine engines are more reliable.

7. i like taking the road less traveled and what better way to put my engineering skills to the test?

8. A much higher power to weight ratio than any reciprocating engine every thought about. --

9. operating costs.....maybe not really sure, i know they have a little (ok a lot) higher fuel consumption. but that is a factor of power. i would say hp for hp the JE has a better effeciency.

10...because it is so COOL!:D

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1. It is VERY VERY cool! (i am still a kid thats important)

2. Its sounds VERY VERY cool! (see above)

Hard as it may be to believe in something that involves the safety of yourself and anyone else you put in the plane, "cool" is absolutely meaningless. Being a "kid" does not absolve one from considerations of safety.

 

6. there is less axuillary parts...these engines need fuel and air. less things to go wrong. I personally believe that turbine engines are more reliable.

This is one of the two things you're right about - TBO of certificated turbine engines is far higher than TBO of certificated piston engines. Non-certificated for either - who knows.

 

8. A much higher power to weight ratio than any reciprocating engine every thought about. --

While true, what are the consequenses? If you end up going faster than the Vne of the aircraft, what happens? If you end up going faster than the critical mach number of the canard, what happens? Do you know?

 

9. operating costs.....maybe not really sure, i know they have a little (ok a lot) higher fuel consumption. but that is a factor of power. i would say hp for hp the JE has a better effeciency.

If you would say that, then you don't know what you're talking about.

 

For equal power/thrust output, the turbine's efficiency is on the order of 2/3 of the equivalent power piston engine. It will use at least 50% more fuel to perform the same task. You will vastly lower your time aloft and range. Anything you would have gained by going faster you'll lose in the fuel stop that the piston engine doesn't have to make, and they'll get there a lot cheaper, too.

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while i appreciate your comments. how did me saying they are cool, lead into the conversation of safety? umm...ok well every jet pilot must be unsafe because they are using a jet engine..... would an f-16 or a raptor be cool with a prop? NOPE! But thanks, i am fully aware of the consequences of my actions. Now, while these before mentioned aircraft are designed around this paticular powerplant. i can think of a few canard style planes that are based around a jet engine as well. Are they unsafe? I never said i had any intention of breaking any Vne unless i have engineered other things to keep that in check. Do you have the impression i was going to build a plan designed for a RE with a 150hp and simply modify the motor mounts and drop in a 350lb jet engine will close to 850ftlb thrust? if that is the case then you are mistaken. Obvioulsy since i started the thread with the intention of learning about airbrake...somethink not equiped on the standard cozy, i must be doing some design changes?

What happens if i pass the critical mach number of the cozy? what happens if i just want the extra power to take of on my own personaly run way, that happens to be shorther than the average commercial runnway? i would say that a higher power to weight ratio would be a good thing. No where in my list did i say...cause i want to go faster than the prop cozy. So before you go ASSuming things, why dont you stop being my mom and be practical. Maybe i am a kid, maybe i am someone that knows everything, or maybe i am here just trying to learn more about this paticular aircraft.

 

I think your ranting was a bit premature. cool, you want to take your plane cross country...maybe i want to just fly around on 50 gallons of fuel and come back to the same airport i left. What does that matter. I think jet engines are COOL, and people that dislike my opinnion can go :thumbsup: their (*)

 

Sincerly,

 

Another cozy builder <^>(-_-)<^>

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The reason the transition was made from piston aircraft to jet is the reliabilty of the turbine. Because all of the motion is continous rotation vs. the opposing motion of the reciprocating power plant.

 

A compromise between the two (IMO) is the rotary.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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Richard, while i respect your opinion, may i ask why you do not care for the turbine engine in this plane? you obviously made a point to mention it, and i would love to hear why.

 

My biggest concern is the danger of overspeed - flutter, structural failure or mach stall. If you keep it below a realistic Vne, fine. That's what Greg Richtor is doing. But without the prop on the back making drag, when you're coming down the residual thrust and the clean airframe brings up your speed very, very quickly.

 

We don't know what these planes will do if they hit critical mach. The canard might stall (lawn dart, death) or the main wing might stall (massive snaproll, probably over-G, but not pretty no matter how you look at it.)

 

My second concern is the prodigious fuel burn. You don't get much range OR time aloft with the tankage we have available, and even when you throttle back your fuel burn doesn't drop by much. Look up the Foland Gnat crash in Bossier City, LA in 1991 - he only had 90 minutes total fuel capacity. One missed ILS approach, and he didn't have the fuel to make a second. Double fatal.

 

Another is low accelleration. Thrust from a turbojet is not 1:1 comparable to a prop, it's a more complex relationship than that. But you won't be leaping into the air. Count on long runways.

 

9. operating costs.....maybe not really sure, i know they have a little (ok a lot) higher fuel consumption. but that is a factor of power. i would say hp for hp the JE has a better effeciency.

Not even remotely. If you honestly, really think that - rethink building an airplane. You don't have the basic understanding needed to build and fly safely.

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If you would say that, then you don't know what you're talking about.

Perhaps the scope of that statement should have been qualifed so as not to be entirely broad.

 

However...

 

So before you go ASSuming things, why dont you stop being my mom and be practical.

and...

 

...people that dislike my opinnion can go :thumbsup: their (*)

and...

 

<^>(-_-)<^>

Marc's intent was not to offend or make you feel small, it was basic information relating to the topic. Before you lash out against the next well-respected person in our small community, I suggest you rethink what you're trying to accomplish whether in the real world or a day dream.

 

Turbines are cool, yes -- I agree, but you're getting valuable feedback here that your ego is preventing you from absorbing gracefully, if at all. Results with your approach may include "nah nah, I told you so", but don't forget "dangerous" and "disastrous". Personally, you'd be much better off with a dose of humility and respect as you go through the information gathering phase.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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JetA;

 

IMHO, A turbine/EZ combo pegs the "Cool-O-Meter".

 

SO, The mission statement for the plane would read something like "generate loud noise, and off scale cool factor".

 

Other than the cool factor, the useful utility of the plane just isn't there. Forget long range and economic travel. The factors presented my Richard and Marc are indeed true.

 

With that said, If somebody dropped off a good candidate turbine at my shop, I'd slap that baby in a LongEZ airframe in a heartbeat. Over the years I've been keeping my eyes open for a candidate turbine, here are some of the limitations I came up with during my research:

 

1) Need a turbine with a minimum of 250 - 350 lbs static thrust. (1/5 - 1/4 aircraft gross weight, minimum). I don't think the "Turbo-charger" turbines are capable of this magnitude of thrust.

 

On the subject of thrust, My MT prop puts out approximately 900 lbs thrust at full power/zero airspeed. This thrust quickly drops off as the airspeed increases. (My EZ will press you into the seat on takeoff roll)

 

Depending on altitude (say, below 10k ft), my 160hp piston engine with MT prop is supplying approximately the same thrust as the turbine would, BUT, at 1/3 the fuel consumption.

 

This is the biggest challenge I've encountered, finding a turbine that meets the thrust requirements, but won't break the bank.

 

2) Need long runways, i.e. 5,000 ft - 7,000ft (plus) for takeoff.

 

3) Fuel burn between 20 - 30 gph (even at idle).

 

4) Speed brakes that can be deployed at any speed.

 

5) Vne 220 kts - need to be very careful as the airframe could EZ-ly exceed this. (Must perform stringent flutter testing to 1.2 x Vne)

 

6) Money pit, WAG, $40 - $60 k for the engine and airframe modifications.

 

JetA, I'm with you, I love the smell of JP-4 in the morning. :-)

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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Sooo, after re reading my last post, i realized that i may have come off as an arse...well more than usual. Looking back i could have been a little more diplomatic in my writing. it is hard to not get offended when you cant see exactly how it was intended. with that being said, i appologize for that. i will take Marc's post as helpful instead of an attack.

 

1) Need a turbine with a minimum of 250 - 350 lbs static thrust. (1/5 - 1/4 aircraft gross weight, minimum). I don't think the "Turbo-charger" turbines are capable of this magnitude of thrust.

A GE t-58 is more than capable of that. I was not saying i was going to use a "turbocharger turbine". I was mearly implying that i like JE and have built them.

 

Need long runways, i.e. 5,000 ft - 7,000ft (plus) for takeoff.

Why do you say that?

 

Speed brakes that can be deployed at any speed.

And the reason i opened this topic......

 

Vne 220 kts - need to be very careful as the airframe could EZ-ly exceed this. (Must perform stringent flutter testing to 1.2 x Vne)

 

Can you do this with your prop? or some other prop, RE engine combination? Yes, this is a responsibility thing.

 

Maybe i could program the JE to defuel when this speed is reached?

 

Money pit, WAG, $40 - $60 k for the engine and airframe modifications.

Intial engine price (7k-16k) military surplus - overhauled with 0hrs

Conversion from a shaft to a jet. 300$-1000$

Modifications to orginally airframe. Hard to say for an already built, but i will be building around this powerplant.

 

JetA, I'm with you, I love the smell of JP-4 in the morning. :-)

I love the smell all day long!:D

 

I will agree with you and most others that have spoken out. This is probably not a cost effective modification to this airframe. But that has never been my intention.

 

Turbines are cool, yes -- I agree, but you're getting valuable feedback here that your ego is preventing you from absorbing gracefully, if at all. Results with your approach may include "nah nah, I told you so", but don't forget "dangerous" and "disastrous". Personally, you'd be much better off with a dose of humility and respect as you go through the information gathering phase.

True, I was a bit quick to get defensive...I am now a sponge

 

Not even remotely. If you honestly, really think that - rethink building an airplane. You don't have the basic understanding needed to build and fly safely.

Richard, i can assure you that i am more than qualified make the necesicary safety precautions and design changes to make this airplane safe and reliable. I dont know everything, and i never will. But i can learn what i need to. When i made that statement, i am not entierly sure what i ment, but it wasnt what i wrote. regardless, sounds like you have 3 issues with this...going to fast, not being able to slow down and not enough fuel. I was trying to address one of those very issues.

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Need long runways, i.e. 5,000 ft - 7,000ft (plus) for takeoff.

 

Why do you say that?

 

Pure turbojets are great on the high end of the speed range, and are awful at the low end. F=M*A and when they aren't moving fast, they aren't Aing much M. Even the hottest modern fighters, the ones with a better than 1:1 Thrust/Weight ratio, take off with reheat (afterburners) on.

 

Money pit, WAG, $40 - $60 k for the engine and airframe modifications.

 

Intial engine price (7k-16k) military surplus - overhauled with 0hrs

Conversion from a shaft to a jet. 300$-1000$

 

You can get an engine that will run for that much, but I wouldn't stake my life on that engine continuing to run. It will be a run out that the military has junked, "overhauled" with sandblasting and paint. For a real zero time engine, add a zero to that price.

 

If you want a turbine that comes remotely close to matching the airframe and you're willing to do it right, get an Allison 250. It will outperform the T-58 in every flight regime.

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I looked on the EZJetInc web site to see if they listed the thrust they were getting out of their T-58s. I couldn't find anything!. I would WAG around 500lbs. !!

 

Most of the jets I flew had about a 1 to 4 thrust to weight ratio. These were generally in the 12,000 lb gross weight range. 5,000 ft available was a good minimum. Turbos or low bypass fans, not like the high bypass you find today.

 

The early EC135s that I flew had a 1 to 6 ratio at gross weight of 250,000lbs(with water injection). I wouldn't even start the engines unless I knew I had 10,000 ft available. I think the early Water Wagon B-52s were about the same or maybe a little worst 1 to 6 or 1 to 7. needing 12,000ft runway at gross weight.

 

 

Oh, by the way, 220kts is easily achievable, even with the prop. Just push the nose over a little and watch the airspeed indicator wind in one direction and the altimeter in the other.:scared:

 

Waiter

 

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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