Diego
Topic Author
Posts: 135
Joined: Mon Apr 23, 2001 7:33 pm

Lear 24/25

Thu Oct 04, 2001 3:34 am

Hi folks, Does anybody know any site where I can find detailed informations about the L24/25 mainly concerning the engine characteristics and handling, or if anyone familiar to the aircraft mech or pilot, is willing to share his/her knowledge with me, he/she will be more than welcome to send me an email at my adress diegoair@yahoo.it
Regards DIEGO
 
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: Lear 24/25

Thu Oct 04, 2001 3:52 am

Hi Diego.

I'm not sure, but I think most Lear 24s used Garret Turbojets for engines. Thus the VERY load noise during takeoff.

One thing I am sure about though, is that a Lear 24 could takeoff and climb to 40,000 feet in only 10 minutes, as well as decend from 40,000 feet and land in only 10 minutes! Impressive eh!  Big thumbs up

Chris
"Just a minute while I re-invent myself"
 
Guest

RE: Lear 24/25

Thu Oct 04, 2001 4:17 am

I am bit curious why you want this information?
Iain
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Lear 24/25

Thu Oct 04, 2001 5:09 am

Well, Diego, I could give you quite a bit of info on the Lear 25 as I have worked on several for many years. However, last time I answered one of your questions, I went into quite a bit of detail and spent a lot of my own time in doing so and you never acknowledged that or said thanks. I don't mean to be petty, but how long would it have taken to say hey dude, thanks for the info. So, for now, NO SOUP FOR YOU!!!

By the way, the Lear 25 has GE CJ60-10 jets on it, not Garretts. Later models like the 35 went to Garrett 731's which is a high bypass fan motor as opposed to the CJ which is a straight jet... just a tidbit and a correction, but no more...
 
learpilot
Posts: 783
Joined: Thu May 10, 2001 11:07 am

RE: Lear 24/25

Thu Oct 04, 2001 6:54 am

Diego,

I fly a 24. What do you want to know?
Heed our warnings or your future will be underpant free!
 
Diego
Topic Author
Posts: 135
Joined: Mon Apr 23, 2001 7:33 pm

RE: Lear 24/25

Fri Oct 05, 2001 2:30 am

Twotterrench if you scrolled down my posts, you would find a post labelled regards where I apologize for not having thanked you at the proper time, bedise that I am interested in the L24 and 25 cos on jenuary more than likely I am going to start my training on it and I am trying to get as much informations as I can to show up in class knowing my stuff, since I have been told that the majority of of the ground is carried out by video tapes. Please tell me as much as you want about it, there is nothing in the world that can quench my desire of learning about airplanes.
 
learpilot
Posts: 783
Joined: Thu May 10, 2001 11:07 am

RE: Lear 24/25

Fri Oct 05, 2001 3:51 am

Diego,

Every 24 and 25 came out of the factory with something different, no two are alike. The engines will more than likely be the GE CJ-610-6 or -8A, both with 2950 lbs. of thrust. There is also a -1 & -4, but I think those were only on the 23's.

As for fuel, again, it depends on the airplane. There are 9 fuel pumps. 4 jet pumps, 2 boost pumps 2 engine driven, and 1 fuel transfer pump in the fuselage tank. On a/c not equipped with a fuselage tank (24F and 25F i think) you won't have the transfer pump for a grand total of 8. These models are rare though. Total quantity: depends on the airplane (get the picture).
Low fuel warning light comes on with approx. 500 lbs/side. It's 1000 on the one I fly (24D with the XR wing).

Mmo: .82

Vmo: depends on the airplane, 308 or 360

Gear and Flap speeds: guess what, depends on the a/c.

AFC/SS (autopilot) inop: .79

Can't use thrust reversers and drag chute at the same time if equipped with both. The exhaust from the engines in reverse won't allow the chute to fully inflate.

Max altitude: FL450

There are about 7 different electrical systems, so I won't even start on them, except for the basics:

(2) 28V, 400A Starter Generators

(2) 24V batteries

For battery starts, must have at least 23 volts if using NiCad batteries, 24 if using Lead/Acid.

For GPU starts, Max 28v and 1100 amps. Any more amperage could over torque the tower shaft in the engines gearbox. (that's bad)

Above FL 370, when you are going to decend, if you pull the power back too far you will lose pressurization. Pull the power back until the cabin rate of climb indicator starts to rise. Below FL370, you can go to idle.

They're great airplanes, it's like a little fighter. Push the power levers forward and point the nose up and hold on. I've made it from takeoff to FL410 in 15 minutes at max takeoff weight (15,000 in the XR I fly, 13,500 normally).

They do great on 1 engine. I blew one at FL430. They'll easily do 300 kts. on the 1 engine.

Stay as high as you can as long as possible. You burn the same amount of fuel at idle on the ground as you do at FL410 in cruise. Fuel burn increases tremendously as you decend.

Have fun!

Heed our warnings or your future will be underpant free!
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Lear 24/25

Fri Oct 05, 2001 5:08 am

I know.. I'm sorry.. I was just being pissy.. on the rag or something.. anyway, anything specific you would like to know from the maintenance point of view, as what the previous poster put up is quite thorough and accurate. Ask me something specific and I will see what i can tell you...
 
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: Lear 24/25

Fri Oct 05, 2001 6:49 am

Hi guys.

Years ago, when I was a ramp worker at Toronto Intl (YYZ), for a large FBO, we owned 2 Lear 35's (as well as 5 Falcons 20's). I remember one night, a ramp worker was showing our 35's to some friends, and while he had them in the cockpit he started turning on electric inverters and other switches in order to light up the panels. Apparently, he accidently moved a fuel transfer switch without knowing it. Even though he shut down the cockpit before leaving...the next morning, our maintanance dept found one of the 35's with it's right tip tank a 1/2 inch from the hanger floor! For some reason, fuel was slowly transfering throughout the night. A mechanical problem occured...triggered by the ramper's actions. Man, did the owner hit the roof! But, nobody was fired. Just a story.  Smile/happy/getting dizzy

Here's some photo's of the Lear Jet types you're disscusing.


Click for large version
Click here for full size photo!

Photo © Joe Fernandez - Aviation Photography of Miami



Click for large version
Click here for full size photo!

Photo © Jason Whitebird



Click for large version
Click here for full size photo!

Photo © Derek Ferguson


Question: What is an INFLIGHT SIMULATOR? The Lear 25 has these words marked on it's left engine. Does this mean it's carrying special training equipment?

Chris  Smile

"Just a minute while I re-invent myself"
 
Guest

RE: Lear 24/25

Fri Oct 05, 2001 9:18 am

THEY ARE NOISY BUT DEPENDABLE
 
learpilot
Posts: 783
Joined: Thu May 10, 2001 11:07 am

RE: Lear 24/25

Fri Oct 05, 2001 1:02 pm

btw, hey Twotter,

I think I remember from one of your posts that you're somewhere in Alaska. Do you work for Era?
Heed our warnings or your future will be underpant free!
 
Guest

RE: Lear 24/25

Fri Oct 05, 2001 1:50 pm

Here's some tips for class...

1. Have ALL of the aircraft limitations for the specific airplane that you will be training in down cold before you show up for class.

2. Ditto for all of the memory items on the emergency checklist.

3. Know what triggers each annunciator light on the annunciator panel and know what the appropriate initial response is.

If you will do those 3 things class will be bearable. If not you will be spending every waking hour trying to commit them to memory prior to the checkride. Now's the time to do the memory work. Don't worry about the technical "nuts and bolts" now that's what groundschool's for.

Enjoy!

 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Lear 24/25

Fri Oct 05, 2001 3:12 pm

Hey LearPilot! Yeah, I did work for Era for about 3 years. Refer to it as having served my sentence. However, got tired of the politics and having to be away from home so much, so I moved my toolbox on down the taxiway. Era is a pretty silly place. Have you worked there?
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Lear 24/25

Fri Oct 05, 2001 4:56 pm

Mr. Spaceman. You don't need to have the power on to put a Lear on it's wing.

There is a set of flapper valves in the wing tank that are supposed to act as check vavles between the wing tank and the tip tank on each side of the wing. They are intended to keep fuel from flowing from the wing back into the tip tank.

If they, for whatever reason don't seal right guess what? Fuel empties out of the wing into the wing tank which then gets weighted down and lower to the ground causing more fuel to run into it.

I have seen four of five different Lears that where parked on a shallow slope sitting there in the morning with the uphill wing pointed to the sky just as sure as can be. Luckily none of them touched the ground.

OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: Lear 24/25

Sat Oct 06, 2001 1:03 am

Hi L-188

Thanks, for that info about how the Flapper valves work. The reason this ramp worker turned on the electrical power was so he could illuminate all the annunciator lights, thus making the cockpit look cool! I believe you have to push only one button to test that all the annunciator lights are working.

The Chief pilot at my FBO (SkyCharter), told me on the sly that they were already having problems with that Lear 35 regarding it's wings slowly tipping during the night. They just wanted the ramp worker to think it was his fault, so he wouldn't take any more friends into the aircraft, and it worked!

P.S. Regarding the question I asked earlier about what an Inflight Simulator was. I later noticed that in the info box, below the Lear 25 (Bottom Photo), it says the jet is a Carlpan "Variable Stability Lear 25". What does this mean?

Chris  Smile



"Just a minute while I re-invent myself"
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Lear 24/25

Sat Oct 06, 2001 6:12 am

Hey Toddler - I was reading your profile and noticed you forgot to list some things under occupation. Shouldn't it say: A&P/Dayshift Lead/Commercial Pilot/Designated Examiner/CFI/Former Kawasaki riding wannabe Harley Guy/Troublemaker? (His name is Daryl... the number is....) Just curious...
 
N737MC
Posts: 619
Joined: Mon Oct 09, 2000 3:29 pm

Please Look At My Site For Pics Of Lears..

Sat Oct 06, 2001 7:05 am

Http://www.geocities.com/aaronmandolesi

This is my temp site. I will have my own domain soon with 500+ shots from my collection of business jets..Lots of Lears...

and while your there bookmark the page if you like it. I will make regular updates with added photos.

Thanks
 
Metwrench
Posts: 715
Joined: Fri Aug 17, 2001 11:25 am

RE: Lear 24/25

Tue Oct 09, 2001 12:52 pm

RE: Lear 20 & 35 series aircraft the tip tank flapper valves are intended to keep wing tank fuel from sloshing back into the tip tanks in flight. They are not intended to keep fuel from entering the tip tanks when the A/C is static on the ground. The tip tanks are emptied into the wing tanks by jet pump action.

Fuel inbalance on the ground is caused by the crossfeed being left open when the A/C electrical power is turned off. The slightest imbalance in this case will allow fuel to drain from the up hill wing to the lower one. In very short order you will have a complete fuel transfer augmented by the heavier wing compressing it's associated main gear strut.

What to do now? Well, the first thing is for all the mechanics to find out which silly pilot or line guy caused this and severely chastise him.

Next, don't move the A/C. Power it up and transfer enough fuel back then make sure the crossflow is closed. Or fuel the other wing to an acceptable level.
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Lear 24/25

Tue Oct 09, 2001 1:25 pm

Metwrench - Don't forget that they only way to get fuel into the tip tank is to fill it on the ground (from the pit or the truck). Once it leaves the tip tank, there is no physical way to transfer fuel back into the tip. So, when fuel imbalance on the ground occurs, the best course of action is to #1 - power up the aircraft and cycle the crossflow valve...wait at least 5 seconds and watch for the amber transit light to go out to ensure that the valve is FULLY closed. #2 - Fuel the opposite (high) wing until the aircraft is level and the fuel balance is within dispatch limits.
 
Metwrench
Posts: 715
Joined: Fri Aug 17, 2001 11:25 am

RE: Lear 24/25

Tue Oct 09, 2001 3:38 pm

Theoreticaly yes, but you and I both know that a static imbalance can occur and one wing can get so full that it will touch, or almost touch the ground. In that situation, I have opened the tip tank tank fuel cap and found the tip tank full. The gravity actuated flapper valves in the tip tanks are not completely tight. That doesn't mean that they won't function as advertised in flight, it just indicates that in a static environment they are not perfect.

Hell, we can't keep fuel from leaking externally from A/C, there is no way we can keep fuel from leaking internaly, ever!
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Lear 24/25

Tue Oct 09, 2001 4:43 pm

Metwrench....I never suggested that those seals where perfect. As you know they are just a metal ring with a weighted piece of rubber on them.

In fact I can remember a certain Lear 35 that had to get them changed out twice because one of the first pair just wouldn't seat right. Didn't have any obvious tweeks in it but it wouldn't want to seat.

You could just sit in the office and watch the wing get lower and lower if it was parked on a grade.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.

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