A Couple of questions regarding the Lear

[sho69607 29]

1.) Is it normal to require 50-60% N1 to get moving during taxi? Even at 70 percent I am moving at like 8 knots. Small engines yes, but it is my understanding the Learjet will start rolling even on idle thrust.

2.) What are the idle power settings through flight? ITT limits, typical N1 ranges, etc.

3.) How do I control the nose up/nose down switches on the pedestal? pressing them does not seem to have any effect with regards to v/s or pitch.

Edited January 24, 2020 by sho69607

[ark 1,288]

1 hour ago, sho69607 said:

1.) Is it normal to require 50-60% N1 to get moving during taxi? Even at 70 percent I am moving at like 8 knots. Small engines yes, but it is my understanding the Learjet will start rolling even on idle thrust.

2.) What are the idle power settings through flight? ITT limits, typical N1 ranges, etc.

3.) How do I control the nose up/nose down switches on the pedestal? pressing them does not seem to have any effect with regards to v/s or pitch.

I find it only takes about 35% N1 to get the Lear35 to start to roll. Note in the Lear N1 is the lower gauge in the vertical stack of three engine gauges, and N2 is the top gauge. With N1 at about 35%, N2 is about 63%.

Suggest you download load the Lear35 manual from the FSW Lear35 product page. The manual explains operation of the primary and secondary trim system and has lots of other useful info.

https://flysimware.com/website2019/flysimwares-learjet-35a/

Also suggest you take a look at some of the other threads in this Lear 35 Forum for operational information. For example, there is this post by FSW's head tech advisor Joe, who is a real life Lear35 Capt.

https://www.avsim.com/forums/topic/557412-learjet-operation-explained-from-a-rw-lear-pilots-perspective/

Al

 

Edited January 24, 2020 by ark

[capceo 117]

On 1/24/2020 at 12:04 AM, sho69607 said:

1.) Is it normal to require 50-60% N1 to get moving during taxi? Even at 70 percent I am moving at like 8 knots. Small engines yes, but it is my understanding the Learjet will start rolling even on idle thrust.

2.) What are the idle power settings through flight? ITT limits, typical N1 ranges, etc.

3.) How do I control the nose up/nose down switches on the pedestal? pressing them does not seem to have any effect with regards to v/s or pitch.

1) I find that it doesn't take anywhere near that power to get the airplane moving in the sim. Something doesn't sound right here. Just like the real airplane, it should only require a bit of breakaway power, and then should taxi on idle, or slightly above idle thrust. As far as small engines go, the LR35 actually has enormous engines from a relative standpoint. 3500lbs of thrust per side. 7000lbs of thrust for an airplane with a maximum takeoff weight of 18,300lbs.

2) This is a tough one to answer. On the ground, the N1 idle speed is around 28-30%. ITT at idle depends on ambient temperature. At altitude, the fuel computer underspeed protection adjusts the minimum idle speed based on altitude. At 41,000ft, pulling the thrust levers to idle results in an idle N1 of around 75%. This is primarly done to ensure that there's enough bleed air to maintain the cabin. Unfortunately, we couldn't simulate this.

3) The Nose UP/DOWN switch on the pedestal won't do anything unless the pitch trim is in secondary mode. That little white toggle is a backup in the event the primary pitch trim stops working. In fact, part of the first flight of the day check is to make sure that switch DOES NOT work when the pitch trim selector is in primary. When in primary, the only way to trim the airplane is to use the trim hat on the yokes.

 

Hope that helps.

[stans 702]

Keep in mind that FSX's ground friction has been the source of taxiing issues forever.  Ground friction can be reduced, but then a crosswind will cause your aircraft simply slide across the ground.  Maybe things will be better in MS's upcoming MSFS.

[sho69607 29]

11 hours ago, stans said:

Keep in mind that FSX's ground friction has been the source of taxiing issues forever.  Ground friction can be reduced, but then a crosswind will cause your aircraft simply slide across the ground.  Maybe things will be better in MS's upcoming MSFS.

I am using P3D unless that problem was carried over from FSX. I don't seem to have these issues with the NGX or the FSL A320, both will roll on idle thrust unless they are heavy. I don't have much knowledge of the Learjet 35, so I don't know if this is normal or not. Being a fairly light jet, I can imagine it would roll on idle thrust.

[sho69607 29]

17 hours ago, capceo said:

1) I find that it doesn't take anywhere near that power to get the airplane moving in the sim. Something doesn't sound right here. Just like the real airplane, it should only require a bit of breakaway power, and then should taxi on idle, or slightly above idle thrust. As far as small engines go, the LR35 actually has enormous engines from a relative standpoint. 3500lbs of thrust per side. 7000lbs of thrust for an airplane with a maximum takeoff weight of 18,300lbs.

2) This is a tough one to answer. On the ground, the N1 idle speed is around 28-30%. ITT at idle depends on ambient temperature. At altitude, the fuel computer underspeed protection adjusts the minimum idle speed based on altitude. At 41,000ft, pulling the thrust levers to idle results in an idle N1 of around 75%. This is primarly done to ensure that there's enough bleed air to maintain the cabin. Unfortunately, we couldn't simulate this.

3) The Nose UP/DOWN switch on the pedestal won't do anything unless the pitch trim is in secondary mode. That little white toggle is a backup in the event the primary pitch trim stops working. In fact, part of the first flight of the day check is to make sure that switch DOES NOT work when the pitch trim selector is in primary. When in primary, the only way to trim the airplane is to use the trim hat on the yokes.

 

Hope that helps.

Ok thanks for your help. I do have the CH rudder pedals so I am wondering if there is an issue with the brakes sticking somewhere. There is no indication of differential brakes being on, but I will try adjusting the null zone and see if that helps too. Also one other thing, are there that many corporate/private operators of the 35 anymore? Looks like it has been retired to mostly medevac and cargo missions now.

Edited January 26, 2020 by sho69607

[ark 1,288]

2 minutes ago, sho69607 said:

Ok thanks for your help. I do have the CH rudder pedals so I am wondering if there is an issue with the brakes sticking somewhere. There is no indication of differential brakes being on, but I will try adjusting the null zone and see if that helps too.

Make sure you are looking at N1, the lower gauge in the stack, and not N2, the top gauge in the stack -- the Lear layout is strange!

Al

[capceo 117]

On 1/25/2020 at 8:15 PM, sho69607 said:

Ok thanks for your help. I do have the CH rudder pedals so I am wondering if there is an issue with the brakes sticking somewhere. There is no indication of differential brakes being on, but I will try adjusting the null zone and see if that helps too. Also one other thing, are there that many corporate/private operators of the 35 anymore? Looks like it has been retired to mostly medevac and cargo missions now.

 

Sure. Despite the fact that it burns significantly more fuel than modern comparative airplanes, like the Embraer Phenom 300 (which I flew at my last job), its still a fantastic value. In fact, the LR35 and LR55 I fly are both executive charter airplanes.

Look at the value proposition this way: If you want a jet that seats 8, cruises at M0.80, and has 2,000nm of range, 5hrs of endurance, and costs less than $2000hr to operate, what else are you going to buy for the same money?

 

So, lets compare the LR35 to the modern day counterpart, the Phenom 300.

The Lear 35 is burning 1400pph in cruise at M0.77. The Phenom is burning 800pph at M0.77. In other words, the Lear burns 208gph, and the E55P burns 119gph.

Now lets assume we operate our airplane 300hrs per year. The Phenom saves you 89gph over the Lear 35, or 26,700 gallons per year. At an average retail price of $5.50/gal, that's an annual savings of $146,850.

Sounds great! Right?

Not so much.

A 5 year old Phenom will cost you $7,000,000.

A decent Lear 35 can be had for $500,000.

So what does this all mean?

It means that for the PURCHASE PRICE of a 5 year old Phenom 300, you could buy a decent Lear 35 and put fuel in it for 5,681hrs, or 300 hours per year for almost 19 years, before the total cost of the two airplanes was equal at $7,000,000.

Obviously, this doesn't take into consideration maintenance, crews, insurance, hangars, etc. But the biggest two deltas between new and old is fuel and purchase price. This example shows why the older Lears are still popular, and still a great value. For the money it would take to buy a newer airplane with the same cabin and performance, you could buy a LR35 and run it for a long, long time.

Edited January 27, 2020 by capceo

[sho69607 29]

12 hours ago, capceo said:

 

Sure. Despite the fact that it burns significantly more fuel than modern comparative airplanes, like the Embraer Phenom 300 (which I flew at my last job), its still a fantastic value. In fact, the LR35 and LR55 I fly are both executive charter airplanes.

Look at the value proposition this way: If you want a jet that seats 8, cruises at M0.80, and has 2,000nm of range, 5hrs of endurance, and costs less than $2000hr to operate, what else are you going to buy for the same money?

 

So, lets compare the LR35 to the modern day counterpart, the Phenom 300.

The Lear 35 is burning 1400pph in cruise at M0.77. The Phenom is burning 800pph at M0.77. In other words, the Lear burns 208gph, and the E55P burns 119gph.

Now lets assume we operate our airplane 300hrs per year. The Phenom saves you 89gph over the Lear 35, or 26,700 gallons per year. At an average retail price of $5.50/gal, that's an annual savings of $146,850.

Sounds great! Right?

Not so much.

A 5 year old Phenom will cost you $7,000,000.

A decent Lear 35 can be had for $500,000.

So what does this all mean?

It means that for the PURCHASE PRICE of a 5 year old Phenom 300, you could buy a decent Lear 35 and put fuel in it for 5,681hrs, or 300 hours per year for almost 19 years, before the total cost of the two airplanes was equal at $7,000,000.

Obviously, this doesn't take into consideration maintenance, crews, insurance, hangars, etc. But the biggest two deltas between new and old is fuel and purchase price. This example shows why the older Lears are still popular, and still a great value. For the money it would take to buy a newer airplane with the same cabin and performance, you could buy a LR35 and run it for a long, long time.

Oh wow that is interesting to know. With how old these aircraft are though, isn't there a problem with them reaching their maximum number of cycles? I am not sure how this compares to larger airliners, but I know pressurized aircraft have a cycle limit. Once aircraft reach this limit, are they non salvageable? Or can they still be maintained/repaired to fly past this limit?