Learjet .40 Build
03-23-2009, 07:09 PM
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RE: Learjet .40 Build
Pat,
If fuselage is matched with the scale of the present wing then it's better to make whole new fuselage as all diementions will change accordingly, that also means we can't use any of the supplied formers, plastic parts or die-cut wooden parts from Great planes for this newer fuselage!
Our main reason to do these mods are to use what we have from original kits and airframes and make some mods accordingly to gain best scale from it or i'm missing something!!
So should i go ahead and see what we can achieve form what we have on hands or develop half new aircraft!...
If fuselage is matched with the scale of the present wing then it's better to make whole new fuselage as all diementions will change accordingly, that also means we can't use any of the supplied formers, plastic parts or die-cut wooden parts from Great planes for this newer fuselage!
Our main reason to do these mods are to use what we have from original kits and airframes and make some mods accordingly to gain best scale from it or i'm missing something!!
So should i go ahead and see what we can achieve form what we have on hands or develop half new aircraft!...
03-23-2009, 07:19 PM
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RE: Learjet .40 Build
I have marked the cut line 1" behind the F2 former on the fuselage, this line goes across to other side also. I want to have some meat to use afterwards to incorporate into newer structure and also assist in reinforcement.
You can see one of the stringers not visible in these pictures, its was badly damaged to the point i had to remove it.
You can see one of the stringers not visible in these pictures, its was badly damaged to the point i had to remove it.
03-23-2009, 07:29 PM
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RE: Learjet .40 Build
Sam i think you may have ment that for me, but none the less what my main question is if the fuese is scale length to the height I would almost leave it alone and leave it stock, if its not scale then I would probably add the 5" plug to see what happens with controlability you know, just my thoughts so far on the project
brent
brent
03-23-2009, 07:55 PM
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RE: Learjet .40 Build
okay here is a pic that i scaled down in paint of an actual lear 35a and the other image is off of back of the manual from what i see here is the location of the wing is the problem. it looks to me if you move it back somehow that would solve the scale "appearance problem" now that being said its still not scale though because of the wing but the side view would look scale however the over head is not and I imagine not sure though but the wing is probably not scale for flyability and stability also notice on the full scale the horizontal pitched up 
03-23-2009, 08:14 PM
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RE: Learjet .40 Build
thanks sebo
i beleive if you are going to go with the edf idea i bleive move the wing back if you can because all the weight is going to towared the rear, now that being said that is probably why gp decided to move the wing forward to help with weight and balance, now this throws something out there to if you do make a fuse plug pat that will move the cg forward a lot and will take more rear weight to balance, the more i think about it pat if i was going to use the glow engine method i would leave it stock, sorry to be bearer of bad news but i beleive you will have a better flying model that way, but also as for the angle on the tail i've never been around a lear or flew one or anything of that type but im going to make a stab at this and guess that the angle could be the jack screw like on larger airliners for trim and when you would load a jet of this type all the passenger weight will almost certainly move your cg forward and you would probably need lots of trim to get it to fly neutral as passengers boarded. I do have a mechanic friend that I will call and ask about it to see if he knows im pretty sure he used to work on a 35a. well now the next hurdle for the edf route is how hard is it going to be to move the wings back [&o]
i beleive if you are going to go with the edf idea i bleive move the wing back if you can because all the weight is going to towared the rear, now that being said that is probably why gp decided to move the wing forward to help with weight and balance, now this throws something out there to if you do make a fuse plug pat that will move the cg forward a lot and will take more rear weight to balance, the more i think about it pat if i was going to use the glow engine method i would leave it stock, sorry to be bearer of bad news but i beleive you will have a better flying model that way, but also as for the angle on the tail i've never been around a lear or flew one or anything of that type but im going to make a stab at this and guess that the angle could be the jack screw like on larger airliners for trim and when you would load a jet of this type all the passenger weight will almost certainly move your cg forward and you would probably need lots of trim to get it to fly neutral as passengers boarded. I do have a mechanic friend that I will call and ask about it to see if he knows im pretty sure he used to work on a 35a. well now the next hurdle for the edf route is how hard is it going to be to move the wings back [&o]
03-23-2009, 08:37 PM
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RE: Learjet .40 Build
Yes i see what you are saying Brant and yes earlier pm was meant to you not Pat, sorry.
Even though if you do the wing back, then length of model's fuselage is not to scale length, it's just not the optical illusion here we are seeing. Fuse will have to me extended further forward regardless if you move the wing or not.
Now moving the wing back means to re design the new fuselage as it will a lot easier to Vs to modify the model's wing saddle at this point, i don't think moving wing is a good idea here. We rather design whole new scale airplane vs tackling with these models then. That's my opinion.
Somewhere here i have all those bunch of pictures i took at LBPIA of Samaritan Air's 35A back then, i have to find them now to show you guys that moving wing is not a good idea. I also think tip tanks are bit smaller also if you look at the picture closely.
Even though if you do the wing back, then length of model's fuselage is not to scale length, it's just not the optical illusion here we are seeing. Fuse will have to me extended further forward regardless if you move the wing or not.
Now moving the wing back means to re design the new fuselage as it will a lot easier to Vs to modify the model's wing saddle at this point, i don't think moving wing is a good idea here. We rather design whole new scale airplane vs tackling with these models then. That's my opinion.
Somewhere here i have all those bunch of pictures i took at LBPIA of Samaritan Air's 35A back then, i have to find them now to show you guys that moving wing is not a good idea. I also think tip tanks are bit smaller also if you look at the picture closely.
03-23-2009, 09:30 PM
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RE: Learjet .40 Build
sam i totally agree with you that its not scale the only thing i was thinking that by moving the wing would make it more "sport-scale" i think the only reason to move the wing is for my idea of the edf's to help the weight and balance, now by moving the wing it will be VERY critical on the incidince, I beleive by doing this will cause the plane to be short coupled and less stable as well, like a real lear, like i said i've never flown a lear but talked to some that have and they all talk about the lears unstable characteristics especially with yaw, which with a lot of larger planes even the piston twins i flew they had yaw dampners to keep the passengers more comfortable (keep them from puking haha) and it is noticable from the cockpit. thats one reason the strakes on the bottom are installed on a lot of jets and turboprops it helps the stability a lot.
03-23-2009, 09:57 PM
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RE: Learjet .40 Build
So now that we are in agreement what should we do in regards of the stretch, , ,
I don't think it will effect a lot with the weight and balance, i may have to add little bit more weight in the aft fuse to balance it due to slight increased nose weight. I think if we can only get stretch to look as scale and fall into scale, this model will look great in the end.
Plus i think with you idea of EDFs, you can always add more nose weight!, model may become bit heavier or may stay the same weight wise but i bet it's adjustable and workable. Now i can't see these LJ flying as real one does as i remember one of the pilots of Samaritan Air's pilot said climb rate on these is 5000'/minute!, now that's like a fighter jet, no wonder Lear jet is based on Swedish P-16 fighter's design with pax carrying fuselage...
fuselage!
I don't think it will effect a lot with the weight and balance, i may have to add little bit more weight in the aft fuse to balance it due to slight increased nose weight. I think if we can only get stretch to look as scale and fall into scale, this model will look great in the end.
Plus i think with you idea of EDFs, you can always add more nose weight!, model may become bit heavier or may stay the same weight wise but i bet it's adjustable and workable. Now i can't see these LJ flying as real one does as i remember one of the pilots of Samaritan Air's pilot said climb rate on these is 5000'/minute!, now that's like a fighter jet, no wonder Lear jet is based on Swedish P-16 fighter's design with pax carrying fuselage...
ORIGINAL: brenthampton79
sam i totally agree with you that its not scale the only thing i was thinking that by moving the wing would make it more "sport-scale" i think the only reason to move the wing is for my idea of the edf's to help the weight and balance, now by moving the wing it will be VERY critical on the incidince, I beleive by doing this will cause the plane to be short coupled and less stable as well, like a real lear, like i said i've never flown a lear but talked to some that have and they all talk about the lears unstable characteristics especially with yaw, which with a lot of larger planes even the piston twins i flew they had yaw dampners to keep the passengers more comfortable (keep them from puking haha) and it is noticable from the cockpit. thats one reason the strakes on the bottom are installed on a lot of jets and turboprops it helps the stability a lot.
sam i totally agree with you that its not scale the only thing i was thinking that by moving the wing would make it more "sport-scale" i think the only reason to move the wing is for my idea of the edf's to help the weight and balance, now by moving the wing it will be VERY critical on the incidince, I beleive by doing this will cause the plane to be short coupled and less stable as well, like a real lear, like i said i've never flown a lear but talked to some that have and they all talk about the lears unstable characteristics especially with yaw, which with a lot of larger planes even the piston twins i flew they had yaw dampners to keep the passengers more comfortable (keep them from puking haha) and it is noticable from the cockpit. thats one reason the strakes on the bottom are installed on a lot of jets and turboprops it helps the stability a lot.
03-23-2009, 11:08 PM
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RE: Learjet .40 Build
I was going to start on the fuselage plug but noticed i don't have right size of lite plywood to trace and cut newer templates from the originals. I am going to make the plug itself first and then cut the fuselage to attach this plug into it.
03-24-2009, 07:46 AM
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RE: Learjet .40 Build
sam i agree the plug will be the easiest way to make it look more scale and here is a drawing of a learjet side, top and front view, it looks to me if we were to make a scale model we would have to redesign the whole thing because the wing is not scale either because of the trailing edge and etc. I beleive the plug will be the easiest thing to do and and probably the most effective because like you signature says use the kiss method if we were to get to extreme with it then we will end up having a kit still in the box because we would need to redesign everything probably except for a few things like the tail and such, this is just my opinon and think the plug is the way to go after looking at it.
03-24-2009, 07:47 AM
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RE: Learjet .40 Build
here is the drawing and actually from the top view it doesn't look as if the wing is that far off from where it should be on the model, well that throws my other idea out,
03-24-2009, 12:05 PM
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RE: Learjet .40 Build
Here is a great article on full scale thurst reversers with good pics of operation. Its not the TFE-731 with a Dee Howard reverser which most LJ-35A's have but its close enough in its operation.
http://www.hilmerby.com/md80/md_reverse.html
http://www.hilmerby.com/md80/md_reverse.html
03-24-2009, 12:11 PM
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RE: Learjet .40 Build
ORIGINAL: vupilot
Here is a great article on full scale thurst reversers with good pics of operation. Its not the TFE-731 with a Dee Howard reverser which most LJ-35A's have but its close enough in its operation.
http://www.hilmerby.com/md80/md_reverse.html
Here is a great article on full scale thurst reversers with good pics of operation. Its not the TFE-731 with a Dee Howard reverser which most LJ-35A's have but its close enough in its operation.
http://www.hilmerby.com/md80/md_reverse.html
OK Chris....that article is awesome!! Exactly what I needed. With all the talk of fuse plugs, and non scale wings I now have a new plan for the second LJ kit.......Buy a mark frankle LJ plans kit, fit it with 2 turbines and thrust reversers.
03-24-2009, 04:01 PM
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RE: Learjet .40 Build
ORIGINAL: vupilot
Here is a great article on full scale thurst reversers with good pics of operation. Its not the TFE-731 with a Dee Howard reverser which most LJ-35A's have but its close enough in its operation.
http://www.hilmerby.com/md80/md_reverse.html
Here is a great article on full scale thurst reversers with good pics of operation. Its not the TFE-731 with a Dee Howard reverser which most LJ-35A's have but its close enough in its operation.
http://www.hilmerby.com/md80/md_reverse.html
B732s also have similar bucket style thrust reverse's as on MD 80s...
03-24-2009, 04:03 PM
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RE: Learjet .40 Build
ORIGINAL: brenthampton79
sam i agree the plug will be the easiest way to make it look more scale and here is a drawing of a learjet side, top and front view, it looks to me if we were to make a scale model we would have to redesign the whole thing because the wing is not scale either because of the trailing edge and etc. I beleive the plug will be the easiest thing to do and and probably the most effective because like you signature says use the kiss method if we were to get to extreme with it then we will end up having a kit still in the box because we would need to redesign everything probably except for a few things like the tail and such, this is just my opinon and think the plug is the way to go after looking at it.
sam i agree the plug will be the easiest way to make it look more scale and here is a drawing of a learjet side, top and front view, it looks to me if we were to make a scale model we would have to redesign the whole thing because the wing is not scale either because of the trailing edge and etc. I beleive the plug will be the easiest thing to do and and probably the most effective because like you signature says use the kiss method if we were to get to extreme with it then we will end up having a kit still in the box because we would need to redesign everything probably except for a few things like the tail and such, this is just my opinon and think the plug is the way to go after looking at it.
, now i'm getting the wood and will start making the plug soon
.....
03-24-2009, 05:37 PM
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RE: Learjet .40 Build
cool let me know how it turns out, one question i have is since ill be putting the power section of my lear in the back i should be able to eleminate a lot of weight on the nose since I wont have an engine on the front it looks to me that i could save significant weight by reducing the doublers fire wall and such that is needed to hold and engine on the front, imay be able to get rid of the ply ahead of the wing and go directly to balsa, shouldn't I?
03-25-2009, 02:33 AM
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RE: Learjet .40 Build
Sorry i couldn't reply earlier, i had severe back pain whole day today and was asleep due to medication's effect. No don't remove the ply where wing mounts on as you need strength there to hold the wing with the fuselage, actually i would double it if i were you. Yes with lack of engine in front you can go with balsa former vs ply as it's not needed there anymore as firewall. Other thing is whole nose section could be made out of fiberglass as one piece, that will eliminate a lot of present frontal weight. You can then use that area to place batteries or servos there instead in the tail, this way proper weight could be distributed evenly. I thing we can then place the nose retract in right position as on backwards presently!....
I will start of fuselage plug in day or two,hopefully over coming weekend, i will have fuselage stretched, sheeted and ready for covering once again...
I will start of fuselage plug in day or two,hopefully over coming weekend, i will have fuselage stretched, sheeted and ready for covering once again...
03-25-2009, 06:59 AM
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RE: Learjet .40 Build
cool yeah i was going to leave the ply around the wing mount area and then change to balsa about 2 to 3 inches in front of the wing i mean if im going to stretch the fuse i might as well go ahead and get some weight benifits too you know
hate to hear your back is bothering you hope you get better soon
hate to hear your back is bothering you hope you get better soon
03-25-2009, 09:06 AM
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RE: Learjet .40 Build
Hey Brant,
Thanks for thinking of me, yeah every so often my back pain acts up pretty painfully and i have to take my meds and it puts me to sleep for good 12hrs...
As for formers, i have to see whats the best way to do it due to weight issues we have. I am thinking to make section plug itself with 3/32" lite ply formers as in the kit and then add another two one on fuselage and other on nose section separately. This way when i attach this plug it will be attached to another former also. Plus to open up slots on the side of the formers for reinforcement with strip of light ply to be added butt against side frames.
Or to make 1/4" formers and use half the width for plug stringers and other half for fuselage stringers on fuselage side and use two 3/32" formers on plug to nose section...
Thanks for thinking of me, yeah every so often my back pain acts up pretty painfully and i have to take my meds and it puts me to sleep for good 12hrs...
As for formers, i have to see whats the best way to do it due to weight issues we have. I am thinking to make section plug itself with 3/32" lite ply formers as in the kit and then add another two one on fuselage and other on nose section separately. This way when i attach this plug it will be attached to another former also. Plus to open up slots on the side of the formers for reinforcement with strip of light ply to be added butt against side frames.
Or to make 1/4" formers and use half the width for plug stringers and other half for fuselage stringers on fuselage side and use two 3/32" formers on plug to nose section...
04-07-2009, 08:21 AM
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RE: Learjet .40 Build
Hey Pat & Brent,
Sorry for the delay, i'm sure you guys must be thinking that i would have my LJ already by now,
well that's not the case. It's just sitting the way it was in above posts. I had decided to get my S Connie project on the works again, so that's what i'm working on now. It's big project ans i want to finish it this year so i can fly it. If i get time from it's mold making process, i will definitely work on LJ again and finish it. Please carry on with your builds on here as i will keep watching your progress.
You guys are welcome to chime in on my S Connie thread if you want, http://www.rcuniverse.com/forum/m_4538333/tm.htm
Sam
Sorry for the delay, i'm sure you guys must be thinking that i would have my LJ already by now,
well that's not the case. It's just sitting the way it was in above posts. I had decided to get my S Connie project on the works again, so that's what i'm working on now. It's big project ans i want to finish it this year so i can fly it. If i get time from it's mold making process, i will definitely work on LJ again and finish it. Please carry on with your builds on here as i will keep watching your progress.
You guys are welcome to chime in on my S Connie thread if you want, http://www.rcuniverse.com/forum/m_4538333/tm.htm
Sam
04-07-2009, 08:48 AM
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RE: Learjet .40 Build
I have not made any more progress with mine either, other than running a tank of fuel through it. I have been concentrating on getting everything I need for my t-rex 600/airwolf project, also other things going on not leaving much time for my hobby.
04-08-2009, 09:57 PM
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RE: Learjet .40 Build
ORIGINAL: Props4ever
I guess we are on same stage then...well if you do fly here, make sure you make video of 2nd flight for us to see....
I guess we are on same stage then...well if you do fly here, make sure you make video of 2nd flight for us to see....
I will have to see if I have a way of making a video, i think our camera uses tapes....need to get a digital one. It will be the first flight, the tank I ran through it was on the bench.