olnico

...

heliman48

Para : Deleted

salibaj

Is there any article of how to balance the stabs?

Regards

Joseph

olnico

Joseph,

I am going to publish an article on RCU on flying stabilizers soon. The text is complete and I still have to get some nice pictures.
That should come up within a few days.

salibaj

Thanks Oliver,

I would appreciate if you mention in which month it would be published. I used to be a subscriber for RCJI but unfortunatly there was time when only adverts where of interest in this magazine.

Regards

Joseph

olnico

Hi Joseph in RCU, not RCJI
Meanwhile you can have a look here:
http://www.rcuniverse.com/forum/m_91..._1/key_/tm.htm
and here ( much more theoretical at the end ):
http://www.rcuniverse.com/forum/m_89..._1/key_/tm.htm

salibaj

Ooops, sorry for that. I must still be drunk

Regards

Joseph

olnico

Lucky you...

rhklenke

My Feedback: (24)

Oliver,

I would LOVE to have a subscription to RCJI and would gladly pay what it is worth to read articles by very knowledgeable jet guys like yourself. Unfortunately, even though I did get a subscription setup one year at Florida Jets, I was never able to get it renewed or get a new subscription via any other method even after many, many, many, many tries... [&o] [&o] [&o]

Bob

Mr DJ

...

Mr DJ

...

Mr DJ

...

heliman48

Kevin & All

Do you have a brief outline on how you balanced your Stabs . I am only interested in the procedure , And by the way To all : as I wrote before Oliver I signed up with RCJI , I believe in supporting this hobby and hate to see Info of this caliber go wasted ! something the MFG should get in tune with ASAP ! By the way late night reading was a success . It makes me feel good that I had implemented two of your Heavy Duty procedures Landing gear using the west 124 system carbon fiber top and bottom on gear plates & tank reinforcements using the same method .

Cheers Nate

olnico

Nate, consider putting the gear on flex plates. It will save the internal structure with the time. Please refer to page 61 of this thread.
http://www.rcuniverse.com/forum/fb.asp?m=8945367

These are composite flex plates that will absorb the landing energy and eventually break. The gauge of the plate and composite assembly is important.

Please also have a look at the list of points to watch closely here:
http://www.rcuniverse.com/forum/m_92..._1/key_/tm.htm

heliman48

Oliver

I have G Plate 1/8 thickness on all of the landing gear blocks as indicated in your page 61 of the forum ,as well I did a lay up carbon fiber & epoxy top and side walls , I think that over kill due to the fact that I also used another 1/4 inch ply both front and rear of the new gear blocks installed with Hysol glue , One thing I noticed on a set of gear blocks that some used a piece of G plate or a build up of glue was used , From what I understand this is to angle the gear frame on the attachment blocks to give a wider stance , I did notice the wear and damage to the gear housing , is this the fact that the uneven attachment points to the plates is causing this type of fatigue due to improper mounting of the gear frames . (not being flush to the blocks ) ?
I also noticed that the countersunk screw had some lateral play and oblong wear in the aluminum housing , In past did FEJ manufacture a gear kit ? I had a gear kit sent to me from Ted & CY in Ontario Canada , was this something the Canadian Boys made or was it shipped from James at FEJ ? do you know anything about this ?
Also as I said before I think that your input to this form is outstanding ,It has answered allot of my Questions . All you have to do is read out side of the box !!

Nate

cy paul

From FLy Eagle

olnico

OK Nate,

Could you post a picture of your setup ?

If I understand well, you have over reinforced the gear plates. You should do exactly the opposite.
The purpose of the flex plate is to be flexible to absorb the landing shock and eventually brake.
The main formers have to be reinforced and made very stiff, the gear plates have to be made flexible.

You can see here the flex plate system:


It is a plywood/carbon/plywood composite plate. The different plates are not glued together to provide the "spring" effect.

The glue build up to tilt the gear was the first prototyping of the new gear geometry. The advantage of this angling method is that the gear does not translate down by 1 inch like FEJ has done in their so called "upgrade".

Bear in mind that the real F-18 has a very specific stance:



Here is what I achieved:



It is over 1 inch wider than the FEJ upgrade kit but more importantly, I have 2 degrees more positive AOA one the ground. This makes very smooth takeoffs:
http://www.geohei.lu/olin/videos/Hob...flight%206.wmv


Notice at the same time the ridiculously slim tires and gear struts compared to the real one...

heliman48

Oliver

What you have done is sandwich the plate in between the two pieces of ply , good Idea ! But , I do not want to be replacing the plates along the way , I have reinforced the main blocks with carbon fibre and the blocks have G- plate glued to the bottom hopefully this will suffice , I will start to look for different springs for the inside of the struts too give me more throw and not bottom out as they do from the MFG, I would like to see the remaining 3/4 of a inch get used up .

I will post some photos this week as I have the flaps & ailerons drying today , the new so called 2nd generation wings are they ply & balsa inside built up ? I heard you speak of foam ?? One of the problems with the F-18 C in Canada was that a negative angle of approach on take off with full fuel and full armament you had to rock it to maintain positive incidence to gain lift , we destroyed one in 1983 in Cold lake due to that fact , So having said that , I want to try and get the most from the strut extension to get positive incidence as it sits now I do not .

Your movie looks good , I fell you need more flap and better fuel management , As for take off NOT BAD , once you get the noise gear issue cleaned up transition will be gentle . what turbine do you have ?

Nate

olnico

Hi Nate,

That was flight number 6. I am now nearing 50 flights with this bird and 1 1/2 year of operation.
I don't think that anyone else has my experience on the FEJ 1/7 scale F-18F.

I strongly recommend you to put the gears on FLEX plates. The rigid plates will destroy your fuselage/internal structure if you get to a hard landing. No matter how much you reinforce them.
Bear in mind that your plane will be around 26-27 kgs fully loaded.

The aluminium gear wall with the tapered screws will give up after around 20 landings.

The nose gear issue is not sorted yet. The gear goes up against the wind and the piston is too weak if the plane picks up speed to early.
I need to design a trailing link strut with a piston to help it.

I have a P-200 in there and that is just what it needs.

David Searles

My Feedback: (49)

"The nose gear issue is not sorted yet. The gear goes up against the wind and the piston is too weak if the plane picks up speed to early.
I need to design a trailing link strut with a piston to help it. "


Olivier,

I eventually installed a separate retract valve and air supply for the nose gear, so that it would not have to share the pressure provided to the mains. Works every time now, no matter the speed! I've also used individual button valves for each gear strut to control the doors for that strut only. Again, works perfectly, no more flying with one gear stuck out into the airstream. The doors only close when that specific strut is fully retracted.

David S

olnico

Hello everyone.
I have sorted out all the landing gear issues on the 1/7th scale F-18F.

1) Nose gear retraction problem:

The problem was coming from the fact that the retract actuator is undersized. The nose gear retracts against the wing and is heavy, especially with the steering servo mounted on the strut.
I measured a retraction effect of only 200 grams force at the wheels. This force would not overcome the drag generated by the aircraft velocity in my case. I could not get the nose gear to retract most of the times ( unless doing a retraction cycle during a hammer head figure ).
So I decided to convert the trailing link into a pneumatic actuator:



The pushrod teflon end was machined to accept an o'ring of the appropriate diameter:


I inserted an aluminium plug at the link root. This plug was also drilled and tapped for the air nipple:


Note that the link is fixed to the fuselage former with a carbon flex plate as shown above.

The nipple is connected to the retraction air line.
The retraction force generated at the wheels is now 800 grams and is more than enough to get a 100% reliable nose gear retraction.

2) Weak retracts:

I have come across a fairly annoying problem: the retracts become sloppy after about 20 landings as shown in my previous post.
The trunion axle screws are countersunk types and the countersunk machining made in the retracts walls ovalize rapidly.



I redesigned the retracts to get them 50% stronger.

I did not change the overall shape of the retract neither the thickness of the walls, only the type of material and the axle.

The retract walls are made of AU4G.
The trunion axle is made of 8mm plain bronze.



I also changed the design of this countersunk screws. The trunion is fitted to maximize the interaction surface with the walls. The mounting flanges are full length to spread the landing efforts more evenly on the mounting plates.
They also block the trunion axle laterally at the same time...



Note the locking slot that is longer on the downlock side. This completely secures the downlock and avoids having the landing efforts damage the walls ( red arrow ).



I proposed to pass this design to Fly Eagle Jets for free, but they totally ignored me...
That would sort out all the gear problems that they have on all their models due to the countersunk screw design.

jetnuno

Hi Oliver

Nice work overthere. I can only imagine the hours and effort spent in this improvement. It really looks nice and I just don't understand how FEJ ignored this R&D for Free.......

I guess they have not quite ignored it. Maybe we will see those improvements in future kits...

Hope you log many gear troble free flights with this set-up.

Regards

Nuno

rbxbear44

My Feedback: (86)

Oliver, guys...
I am all for aftermarket upgrades myself. James and crew are great and I will continue to support and promote FEJ products. So, we are "blessed" with guys like Oli, David and Kevin and I plan on using them regardless. As I will be using the Matrix Gear for the F-16. I would love to have a stronger set up on this plane too. The gear is soooo important! I hate to be thinking, "I wonder if it will work this time" during the whole flight instead of enjoying the moment!!!

Oli...thanks dude!

Rex

olnico

Your welcome guys. It is a real pleasure to have a F-18 with a landing gear that holds the weight of the plane on landing and works 100% of the times.
I'm gonna put a lot more flights on with this plane now.

By the way, I also improved the pitch control on the plane by inserting a 5 mm winded carbon rod into the elevator shaft.
I hysoled this inner shaft and got the torsion and flexion rigidity improved by about 10%. This gives a greater pitch control precision on this plane.

olnico

For information, I did try a takeoff with 0 flaps this week end ( by mistake i must admit [:-] ). The plane jumped again on that one. So it is definitely evident that the more takeoff flaps, the smoother takeoff...
Check out this video for the demonstration:
http://www.geohei.lu/olin/videos/Hob...0Zune%20HQ.wmv

The flight conditions where 25 degrees centigrade and a pressure of 1013 hPa. The P-200 has just enough power to give me 2 vertical rolls and good authority in high AOA maneuvers.
the plane is definitely not overpowered with this engine and I still maintain that this is the perfect power setup for this plane...