JustJets

My Feedback: (15)

CURRENTLY WORKING ON BOTH KITS. I WILL POST MY BUILDING NOTES AND OPTIONS. ANY ONE INTERESTED?

JustJets

My Feedback: (15)

TAMs F18
Will start with tail end of the kits just to give brief over view, TAMs kit has the system here, any one looking at his web site will see it for what it is. Very Very strong and almost zero slop or end play. Servo box is made up of 1/4 ply which is mounted at mid ship supported by aft main wing former. Will use the JR DS8611 servos and included hardware. No changes needed here

SJN

Looks alot like the jetlegent stab. mount.
http://www.jetlegend.com/show.php?sn=18

john agnew

Sonnich

It looks like the Jetlegend elevator bearing because Jetlegend makes the F18 for Tam And his new F16

John

Shaun Evans

Justjets,

Keep up the good work. It's about time someone did this thread. I know many people have been waiting for a no-bones, no-spin, no-BS comparison. This should answer a lot of questions for a lot of potential customers----assuming you're not an undercover shill for one of these outfits, that is......

JustJets

My Feedback: (15)

Hi Shaun
Paid full price for both kits. I have no affiliation with Ether Company, nor do I have the time to push any products. I am a full time military aviator stationed in Germany. These are my kits and my personal opinions only. I do not whish to insult or offend any one who may operate or own either one of these kits. If I seem hard in one or more areas you can bet it will be safety related areas. Please feel free to correct me if I go astray.

JustJets

My Feedback: (15)

SM F18
Was looking at few things that were of concern for me here, 1st seems to be lot of play in this area. Elevator system has radial and end play, almost 3/8 inch of up/down play at tip. End play is not as bad, but I needed to be shimed in place with three nylon washers which will make assembly at flying field impractical. I have used the best hardware available on the market and can’t seem to reduce slop in this area. 2nd, I did notice that the servo mount was flexing when the elevator was in motion. This area could be reinforced with additional wood. However most of my end play is coming from the elevator pivot rod which has a flat machined into its surface. There is approximately 35% material removed from this rod which seems to be the problem area as far as this slop is concerned. I will include a few photos’ that will address my concerns in this area. Not sure that anything will help this type of a set up, or if it will work well or not. My guess is that it will operate fine if kept clean and well lubed at ALL COST. But this area will definitely be a preflight check item. If all else goes well with the kit I may try something different on this control surface.

Shaun Evans

Hey,

Awesome. Now I'm REALLY interested in this thread. That seems like a very strange way to build that stab shaft. Why do you suppose the flat spot is so huge? Also, before you get into the particulars with regard to construction--what was your overall impression of the external airframe? Which one had the better layup, better detail, more tidy, etc.? What do the bare airframes weigh? Thanks!

JustJets

My Feedback: (15)

Hi Shaun
Not sure what SM was thinking on this change. I have two SM F15’s and this modification is absent, (TG). They have eliminated any potential slippage that may have occurred but also have gained some slop in this area which was not there on previous elevator systems. We will have to see how well this holds up under regular use. Keep in mind that the outer bushing has full contact with the elevator shaft, it is the inner bushing were the play appears to be generated from. It is only a few thousands of an inch but that is magnified quite a bit out at the tip of each elevator. As far as the kit goes I have taken 127 photos of these kits so far and will be covering the fuselage and it's construction in detail as I move along. I think in the end you will see it really depends on your expectations of each kit as to which kit one might prefer. Please feel free to call for a more direct answer.

Phil

Aero65

My Feedback: (2)

Phil

Keep up the good work. I will pass your suggestions on to Skymaster for improvements; I'd like to thank you in advance for any constructive criticism that you might offer.

If you have any questions please feel free to ask.

TED ANTON

My Feedback: (7)

Hi Phil


I have a SM F5 and I noticed that when I removed the servo grommets the stab servo could be further tightened to eliminate
any servo movement.
The great thing about turbines is the almost zero vibration compared to ducted fans.

I was at a recent jet meet and compared an Avonds F15 to a Yellow F15 parked right next to each other, I have seen each kit many times( and built 2 F15's) but when their right next to each other you can really notice the similarities and differences.

Keep your post going, it's very interesting so far.


Thanks

Ted

David Searles

My Feedback: (49)

Regarding the flex in the stab servo mounting plate: I had the same flex, so glued right angle ply gussests on each side of the servo, front/rear, top/bottom that took care of the flexing but still had the same slop in the mechanism you're reporting. Though Skymaster does not reccomend it, I decided to static balance the stabs in hopes of reducing some of the slop in the air. Seems to work.

DS

Topgun2mo

My Feedback: (45)

Static balancing could actually make the stab prone to flutter. Everything I have read says only balance to reduce servo load on the ground and alway end up somewhat tail heavy on the stab.

Shaun Evans

Topgun,

You're right. Messing with the dynamic balance is asking for trouble, even if just a little. I won't pretend to understand all the science, but when I had it explained to me by a PhD in AE, it made perfect sense (not to balance the full-flying stab an an F-18), but when it's explained by laymen, it comes out sounding like "...because I heard somewhere that you should..."

Hopefully, the people doing this have servos that are strong enough for it not to make too much of a difference.

JustJets

My Feedback: (15)

Looking at the Stabs one more time before we move on. Refer to the photos below, you will notice that the Tams Stab is a little bigger. Also the pivot shaft location differs by more then one inch. For those of you who were thinking of a parts swap it will entail lots of work and big time aerodynamics questions for example the location of a new C.G. I can provide weights of each individual part but keep in mind that the size and shape vary quite a bit. All up weight upon completion of the project will be the key here.

AirPac Models

Just Jets,
Keep you good work. Any suggestions or opinions are important to us. We will keep improve our products.

JustJets

My Feedback: (15)

SM Fuse sections
Detail is very good! My hat is off to SM in this area. My kit arrived with one small crack about mid ship. It can be repaired but will require an epoxy filling compound. Then I will have to burn in the new rivets over the repaired area. Please keep in mind this is a very detailed kit but it is a stand off model as far as scale detailing goes. As with most kits you find minor imperfections, these ranges from pin holes to former and bulk-head bulges. Formers are a tight fit and in most cases can be seen when model is examined carefully. These areas can also be filled and rivets reapplied. The only area were I feel SM could have done a better job is in attaching the air intakes. This area will require the most work but can easily corrected to acceptable standard. All in all very good details, with a little skill, time and patience’s this kit could an outstanding scale representation of a F18 Hornet. Wing panels fit well as far as alignment is concerned but I will also have to add a little filler to level off the wing shelf.

Ali

My Feedback: (5)

Just Jets.
A very interesting thread. I admire your work and attention to detail. Are you building both planes for yourself to fly?

David Searles

My Feedback: (49)

When just jets gets to the Tam Hornet stab, the assembly manual, written by Bob Violet, will indicate that he chose to partially balance the stab. If it's good enough for BV, I'll take my chances!

DS

JustJets

My Feedback: (15)

Hi Al

Yes I am building both kit for my own use. I will be using a few items from the TAMs jet and BVM parts line in the SM just to have a littel better plane and cut doun on the overal cost. Also plan to use Jet Cats for power, p120 for the SM and Titain for the TAMs.

Topgun2mo

My Feedback: (45)

BV does partially balance the stab to reduce servo load however I don't think it is statically balanced as in an airplane prop...isn't that correct?

Statically balanced the stab would not rotate when only supported by the shaft.

Partially balanced, the stab would still fall "tail heavy" but would require much less servo power to hold at the neutral point when on the ground.

JustJets

My Feedback: (15)

Hi DS
As looks right now I do not plan to balance either Kits stabs. I do agree that BVM has probably the best method for balancing the Stab on the TAM F18 aircraft, but not sure it would be a good idea to apply the same technique on the SM F18. As you can see from the photos the pivot rods are quite different. If the only result is to achieve reduced servo load I think it’s really not worth the effort. Keep in mind that when the elevator transition to flight the aerodynamic load will determine where the stab will balance, and that point will be called the center pressure which may be a long way from the shaft. Bottom-line-up-front, if you don’t have a problem don’t fix it.


Phil

JustJets

My Feedback: (15)

Tam’s Fuse section:
Construction Excellent! Very precise lamination of all formers, I must admit that I would have hard time to epoxy all that carbon fiber ribbon, (Beyond Neat). Bonding of formers is the best I have see yet, not one loose fiber anywhere! All critical stress point have CF laminated top and bottom with ply sandwiched between. See landing gear plate, this makes feel very secure when it comes to the landing of a 36 pound airplane. If you break this airplanes landing gear formers you have had a crash, not a hard landing. Detailing on the fuse is very good with panel lines, vents and scale moldings appropriate for an F18E Hornet. I plan to add rivets, not sure if they will be rub on, or burn in type; they will be a lot of work but well worth it in the end. Looks like the big job here is installing a total of ten gear doors. The BVM instruction manual makes this look quite easy. The instruction manual is done by BVM and it is just like the rest of product, Top Koch work no corners cut! Anyone who has built a BVM jet knows just what I’m talking about here. I plan to use the sequence from this manual to assemble my SM when ever possible. Sanding, primer and a little epoxy filling compound is all that is need to prep this plane and start the construction process.

Shaun Evans

Phil,

That's exactly the way it was explained to me by the PhD (not BV, LOL). The aerodynamic center of pressure will balance that stab when air starts moving over it (that's why the horizontal stab on a Cherokee is heavy until you fire up the Lycoming). Until then, the 300 in/oz servo strength will do just fine in taking care of the tail-heavy nature of the unbalanced stab as you're taxiing around. And YES, it is possible to CAUSE problems by messing around with the relative relationship between the center of gravity and the center of pressure on a full-flying control surface.

Justjets,

Keep em coming!

Gordon Mc

My Feedback: (11)

Thanks for doing the side-by-side comparison ... any chanace you can post slightly larger pics ?

Cheers,
Gordon