rglgatortail

My Feedback: (7)

i studied your pictures a little more mustangman and i see another problem with your setup, your control wires to the retracts i really believe you will have bind problems because the retract servo rotates 180 degrees and the look of your music wire shows that the retract servo cannot rotate the 180 lock to lock without binding and since your outer tubing is spaced the way it is and comes out to the retract servo there is no way the servo will rotate the 180 to lock the gear up or down. I really believe you will have a problem with what you got there dude, i want to encourage you to really study the plans again and complete the retract set up like the plans have you do it. I am using dave browns retracts myself and i am not using outer wire housing because there is really no need for it. You just have to make holes in the ribe just big enough for a clevice to pass thru and the wire to the retracts just have to be carefully bent to go from the servo wheel to the arm to actuate the retract. using outer housings will just make it real hard to set up and sometime down the road make it hard to maintenence the system even though if done right having to do anything to the system is very few and far in between. the music wire coming off the retract servo has to have room to move up and down as the wheel of the retract servo rotates the 180 degrees. I found a video i hope that this helps to demonstrate and just to note that the horn on this servo is way too big for what you will be using.
http://www.youtube.com/watch?v=L-fEWUtehqE
this next video is excellent to show the retract servo not only moving the wire to the retracts but the up and down movement of the wire as well. this is the room that the wire needs to make the system work without a bind and for the retract servo to do it job. take note of the slight bend in the music wire coming from the retract servo horn this is very important. and also note that in the wheel well you will see the wire not only moving back and forth but up and down so this guy is not using outer tubes for the music wire either
http://www.youtube.com/watch?v=GuHB6...eature=related

Mustangman40

My Feedback: (1)

Robert, thank you for the the replies..

I have had the gear in and working and they work silky smooth, the total throw to lock up and lock down is only 3/4". If your using any more throw then that then your wire is just bending inside the wing to make up the forextra throw..

This is from the DB instructions.. "(customer will need to selecta good 180° retract servo with 3/4" total throw"

I will take a vid of them working soon as I put them back in...

Here is another pic,I sheeted the wingsearlier and now you can see where I have to cut the sheetingfor the servo and linkageone the one side.. The linkage on theaft side islow enough to move under the sheeting..I set the fuse on a drew a line showing it's location, plus it gets wingfillets.I have a lot more room then I thought.. I added the 1/4" ply on both sides for the wing dowels and will drill the the dowels right in to it.. I think it is a stronger way then what the plans show. With the way I did it, both W1's are fully glued together with no cut outs in them at all for servos.. To me, it just seemed like you would weaken the wing cutting through the center ribs for two servos...

rglgatortail

My Feedback: (7)

Well if you can get it to work than cool deal. Cutting out the number one rib wont hurt the strenght of the wing and not add any unecessary wood persay, im sorry that my picture didnt come out all that clear but the number one rib is cut away for the retract servo and then a saddle is made to rap around the rib and then 1/8 lite ply is glued in for the servo to mount to. I am curious to see your retract servo work as smooth as you say it does but hey if it works then it works, just keep in mind that when you have built it in now its kinda difficult to go back in and fix it later especially where you put it. remember that the retract servo turns 180 degrees and will not turn off till it makes its complete travel from start to stop so if you have it in a bind it will draw a considerable amount of current approaching 1.5 amps and possiably getting up to 3 amps so make sure that you have it right because the retract servo will take a considerable amount power from the rest of the power system and if you are using a 1100 mah battery well you will drain down that battery in about 45 minutes or less with damage to the power switch wires and the wire going to the retract servo, im just talking about this because i probably have unecessary worry about your setup with the music wire but when i see your video i can probably put my worry off and change it to congratulations and a well done job. I have been wrong before and i maybe wrong again.

Mustangman40

My Feedback: (1)

Now that part has me scared!! The 4-40 rods going to my gear only have to move 3/4" to work the gear fully up or down. My thought was that you can dial the amount of throw on your radio, (which i don't have yet) to get the amount of movement you want from the servo. Am I wrong on this, or can I make to servo only move as much as I want when i hit the switch?
If it does have to move a full 180, then I am screwed on the inboard side. I can open that up so it doesn't bind, but that is not how I set them up...
Guess i better buy my radio this week, I'm going with a futaba 7C if that helps at all...

rglgatortail

My Feedback: (7)

Sorry Mustangman here is the specs on the servo
FEATURES: High torque
Travels 180° - full-lock to full-lock - to hold your gear in position
securely. Not proportional. Perfect for mechanical retract
installation.
Water resistant
Ball bearings
This retract servo and many others like it are NOT PROPORTIONAL that means that you cannot change the servo it will turn 180 no matter what and it will continue to try to get to its 180 turn either in a bind and drawing a bunch of current or if it is setup properly it will start and stop as intended. Like i said you have a problem with your setup and it just will not work. Now that you have gone and sheeted the wing you have a more difficult problem getting in there and making it right. I also believe that where you have the retract servo and where you have to put the wing dowel at you will conpromise the strength of the F2 bulk head because the dowel is so close to the side of F2.
Like i said before i have been wrong on some things and i also had to learn things the hard way i am just trying to help you with your project and give information that is helpful and beneficial to anyone that can use it. I have been building and flying models ever since 1991 and that Ultra Sport 60 is still flying to this day and it is in my gallery. I hope that you can find a way to fix your retract problem. If you like for me to i can take a few more pictures of my wing so the pictures will clarify the installation. What you have got there can be fixed and redone and the sheeting repaired its just that you have that foam material and the outer housing so undoing all of that in a sheeted wing is a pain with out cutting off part of the sheeting from the wing to fix what you have done.
Robert

rglgatortail

My Feedback: (7)

Mustangman watch that second video that i posted and where you see the two easy links that secures the retract wires to the retract wheel that is maybe 3/4 inch the retract manufacturer says that is all it needs is 3/4 inch travel then that is where you put the easy links on the wheel is 3/4 inch apart on the wheel. When you study the video not only is the retract servo rotating from start to stop and pulling the wire 3/4 inch of travel it is also moving the wire in a up and down motion the video then changes to the bottom of the wing and it is kinda hard to see but the owner did not put on the last wheel well from the kit and if you study that compartment where the wheel goes into you can see the retract wire and that wire is moving in an up and down motion. I really believe you WILL have a bind problem and i really hate to see anything happen to a fellow flyer and his or her new Ultra Sport
http://www.youtube.com/watch?v=GuHB6...eature=related

Mustangman40

My Feedback: (1)

Thanks Robert, Iappreciate the advice.. This is the first Mechanical retract that I have ever set up and boy do I feel stupid now... The wing dowels are not a issue any more, they will epoxy into the 1/4" ply that I put in and not have to go all the way back to the main spare...

As far as theservo goes, can I put in say a HT645mg and adjust the movement of it to meet my application? The way the DB are designed, it only takes 5/8" tomove them up and the other 1/8" slides them into the lock position. So oncethey are in the lock up or down, there is no load on the servo.. Forthe life of me, I cant see why that the servo wouldhave to move a full 180 to work the gear, when so little movement does it....

rglgatortail

My Feedback: (7)

retract servos are designed to work in a 180 degrees to create a mechanical lock so it works when it is told to do so and make its rotation making 92 ounces of torque to pull that heavy gear up and into the wheel well it will only take that amount of power for that travel and then turn off it dont constantly keep taking power when it is done rotating like a standard servo, granted that the Dave Brown retracts have that spring that you can adjust to help pull the gear up and into the retracted but it is only a help, if you change to a standard servo that servo always takes power and always using power to hold something that is the reason for the proportional part it starts and moves as necessary but it always using power so if you use a standard servo to move the retracts even using a high torque type standard servo you will still continue using power and the setup that you have where the wire comes thru the outer tubing and spaced the way you do that servo may also continue to pull current all the time just the same scenerio as if the retract servo was in a bind, i dont believe changing over to a standard high torque is the answer either. In the long run you may and this is just you "may" encounter short charge times in your battery because of a current draw from a standard servo trying to keep the retracts in the locked position, If you get the travel and the freedom of the music wire ok then it is possible that the standard servo will do its job but it has to be right and free for movement because any amount of hum from the standard servo means it is pulling current and everytime you change the ATV travel in the radio to get rid of that hum that is less amount of turn the servo will make and that takes away from how far the servo moved to get that retract into the lock position. and dont forget that you will have to use a big enough servo wheel to use to get the 3/4 inch travel to lock the retracts and the standard servo when it has moved the throw you give it, it is still using power still drawing current so be sure you get it right or you could be looking at short charge times from your battery even the battery getting warm or hot and or if you are using 72 mhz radio you could be looking at glitches because of the power loss from that servo in the stalled position or if you are 2.4 and spektrum dont tolerate voltages below 4.6 that is where they are believed to brown out at, futaba could still work at the 4.6 volts but effectively you have less power and less available current to all other servos and less means lowered torque for the servos to move their surfaces

rglgatortail

My Feedback: (7)

take a picture of what you mean of how you are going to epoxy you wing dowels if you want. im afraid that the leading edge of the wing is not strong alone even if you put in a 1/4 in ply right behind the leading edge you have moved the strenght of the wing dowels to the ribs on either side i suppose that might work but in my mind you are putting double duty on those ribs unless the 1/4 plywood is not only going from rib to rib but also up and down sheeting to sheeting to spread out the load and doing that added more wood to the build but that is the fun of building.

Mustangman40

My Feedback: (1)

Robert,
post 943 shows how I have me 4-40 rod set up http://www.rcuniverse.com/forum/m_68...page_38/tm.htm When the gear is in the up position, you can take you hand off the wire and the gear stays up, same when they are locked down. No tension at all to keep them in the lock position, that's why I laid them out like I did. The wing isn't joined yet, so I am going to hold off on doing anything else till i get my radio. If I need to open it back up to get it right, it will be easier to do so before it's all together... I have heard so many people on here say retracts are a PITA and I was thinking that it wasn't bad at all. But now, I agree, they are a BIG PITA!!!!!

rglgatortail

My Feedback: (7)

Only a PITA to get them set up properly and the pictures that i went and looked at yeah you have that part just fine, its just that in my opinion of how you have the retract servo done up. Now that you tell me that you do NOT have the wing glued together then you are just fine, i recomend that you can take this time and make the changes that the plans call for and do not take short cuts that i have to say that you are doing. I understand how the retracts work i really do im just trying to make sure to help you to understand how to set up these PITA devices to enjoy for a long time to come. I took these pictures with a normal kodak camera that is i think five years old so i could only get close enough without it getting too blury so this is the best that i can do. Make your changes to the wing now since the wing is not glued together like you said and make it right that way you will get past this PITA sequence of the build. In a nice way when i say (and a chuckle) this it is only a PITA when modelers make changes and not prepared to study up on how to fix or rectify the problem that they got them selves into but that is why there are modelers with knowledge to share to help out the modelers that is going thru a PITA part of the build.

Mustangman40

My Feedback: (1)

Robert,
thank you very much for taking the time to explain it all, it make perfect sense to me now.. I will make the changes now, it shouldn't be to bad at all...

Jimbo

frank99

My Feedback: (29)

any one care to guess the value of a us 1000 with a super tiger 3000 never started ,plane is a 7.5 thanks frank

rglgatortail

My Feedback: (7)

how about posting a picture of it and let some of us rate it so take several pictures and describe what the plane comes with gotta give more info than that frank

frank99

My Feedback: (29)

rg forgive me ,a little more info and some pics are coming thanks frank

n7188u

Just an update on getting acquainted with the US60. It is truly getting better and better and I am starting to understand what the hype about the US60 is all about. It truly is a great flying airplane. two weekends and I have gone through the first gallon

This thing is truly docile at slow speed (at least mine is) but I have found the following to get a good slow landing plane:

Work on the CG until you find a rearward location where you still feel good about it. I started with the CG at the aft limit. Not necessarily recommended for a first flight but after hearing all the complaints about running out of up elevator during landings I decided to go that way. Worked well for me. I think this is imperative to get a decently landing US.

Another thing I tried yesterday that worked very well was to mix a little up elevator trim when the gear is down (retractable). I don't have flaps and this really helps slowdown for a nice short landing. Honestly, my plane is so docile that it can be slowed down to a crawl without any loss of control. The problem is forcing yourself to fly it that slow. If you are not doing 3 point landings (taildragger) you are coming too hot.

And by all means go retracts if you don't mind the extra work (which it truly is). This thing is sleek with the gear up. I used Great Planes 60 retracts and they are working well.

Chris

dash008

My Feedback: (1)

Thanks for your post. My US has always landed hot. I will work on getting the CG moved back.

Zor

dash008,

Think about the reasons for the CG location and its range of acceptable positions.

It has nothing to do with the approach speed of the model.

The approach speed is what the pilot makes it.

Remember that the speed is controlled with elevators and rate of descent with power.

The pilot has to learn how to control both.

Zor

Mustangman40

My Feedback: (1)

The UPS man brought my new radio this morning, so i got to hook up the gear and see if they worked like I wanted.. I guess I got lucky, a little fine tuning and they were working fine with the servo in the locationI wanted it in.. I am trying to load a vid of them working, but either the site is having problems or it's my computer...

I can get moving forward again, going to glue the wingtogether after dinner and set up the flaps, ailerons and get the wing tips done...

n7188u

Zor,

I agree in that the forward CG is not the reason for being able to fly slow, it is the tendency of the plane to keep its nose up with little trim change during an approach and increased up elevator authority that helps you fly slower. However, let it be known that an aft CG will cause the stabilizer to reduce its downward lift a bit and have a small effect on reducing stall speed (very small effect and not referring to accelerated stalls).

I explain: a forward CG will result in running out of up elevator before speed can be reduced to a minimum point before reaching stall angle. A forward CG also causes the nose to drop down more as speed is reduced requiring further up trim to keep the nose up and speed low. Granted that it is not the CG that is at fault but in RC we tend not to use the elevator trim as much as we should during approach and the tendency is to allow the nose to drop and the plane to fly faster in the approach.

In any case, I warn anyone reading this that a CG that is too far aft is a dangerous condition since the aircraft becomes more sensitive to control input and loss of control could occur. I am learning, and it has been stated in previous posts, that the CG range shown on the US60 plans seems to be quite conservative and that the plane does fly very well with a CG close to the aft limit.

BTW, there is a good link in this forum that goes deep into the subject. Be warned that there are two opinions expressed in the thread and you have to decided which is right My opinion is that there is a change in "Straight and Level Slow Flight Stall Speed (non accelerated)" with change in CG. But it is small to insignificant in RC.

http://www.rcuniverse.com/forum/m_64...tm.htm#6923378

Chris

Zor

Thanks n7188u for your posting and intelligent reasoning.

A couple of things I differ with you.

I will first go ans study the link you showed.

I will be back and explain the items where I differ.

Regards de Zor

Quikturn

My Feedback: (12)

Well put Zor. I would argue that with a forward CG the airplane cannot stall. It enters a decent. Moving the CG more rearward gives the elevator more authority to stall the airplane. Many of the airplanes I fly do this as I can have full up elevator, throttle to idle and still maintain directional control in a decent. In fact, I don't trim the elevator on approach to landing. I like to feel about 50-80% up elevator when landing because it tells me I'm at a good landing speed. As far as a good CG goes I like to have it back to the point where full up elevator at idle will just barely stall the airplane.

Zor

As promissed, I am back.
Some red inserts are from me Zor.
Some reader have a concept that arguments are derogatory.
I do not think so. Arguments are what a discussion is made of.
If a reader cannot accept a diverging statement, a differnt understanding then that reader should stop reading right here unless he is looking for writing degrading comments.
I do not intend to write a volume on aerodynamics.
I only wish to discuss the effect of the CG location in relation to our models behavior.

Well Chris, you did not open the can of worms, I did and I can take all the coming degrading remarks.
I got used to it by now including the PM that I do not bother responding to.

Best to you and all readers de Zor

yukonflier

Zor and Chris,

Thanks for the info on CG effect on landing speed. I'm trying to get this figured out for myself, and appreciate the different theories being brought up. While they may not give me a 'black and white, right and wrong' answer, they do provide material for consideration in my own decisions and experiments...

I will read both arguements, and use that info to come to my own conclusions


Thanks for the help [8D]

n7188u

Thanks for the detailed reply Zor.

I read your notes and I believe we fundamentally agree on the subject.

I hope that it wasn't anything I said that made you upset. I actually enjoy healthy discussion on technical terms. I think your post was concise and expressed your opinion well.

Chris