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RCM Ultra Sport 60 mods

Old 07-10-2008, 08:49 AM
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prgonzalez
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Default RCM Ultra Sport 60 mods

For those US60 scratch builders from RCM plans. I am starting a US60 from RCM plans and I have some questions:

1. Have any of you used double rods for controlling the elevator halves?

I do not have music wire for joining the elevators and at this point I am not sure I want to invest in a wire bending tool.

2. What is the tendency of this build on being tail or nose heavy?

I made the stab hollow using a frame using 3/16 sticks plus two 3/32" skins thinking on building light. I am also considering hollow fin and rudder.

3. I will add flaps sized at 30% of aileron length.

4. I have a set of GP 60-size retracts. What are you guys using?

5. Any recommendations on other points?

Thanks in advance for your help.

Pedro
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Old 07-10-2008, 10:06 AM
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XTOL
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Default RE: RCM Ultra Sport 60 mods

1. Split elevator is an unnecessary complication. The elevator joiner is small
and can be bent with hand tools. Thats how I did mine.

2. I was concerned about tail weight as I was building mine because
of the very thick tail surfaces. But mine came out nearly perfect
with very little added weight necessary. It depends on what you
are using up front for a motor. If you are using something larger
up front than a standard 61 you will need that weight in the tail.
Making the tail lighter is not good if you end up having to add lead
to balance.

3. Flaps work well on this plane. Well worth the effort.

4. I made mine a tail dragger with fixed gear. Depends on your field.
If you have a rough field you will have problems with those retracts.

5.This is a well designed plane and I would be hesitant to modify it
much. Its nearly perfect "as is". Resist the temptation to over power it.
It just doesnt need it.

Dont know if you saw my US60 build page...check it out here:

http://tesla-2.dyndns.org/~mhammer/us60/

I have over 100 flights on mine and its still the best sport plane ever...
Old 07-10-2008, 10:53 AM
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Default RE: RCM Ultra Sport 60 mods

Mike,

Great web site!!!

I have a used 0.S. 61-FX with new ceramic bearings for this model. I read it is enough power for it.

Our runway is made of concrete and is semi-smooth surface.

- Did you use 1/8" music wire as recommended for the elevators?

- Where did you get the music wire, LHS, Hardware store?

I saw your model came out heavier than expected.

- How do you see that overweight affecting your model?

- How is your vertical climb performance?

I am getting used to have unlimited vertical in my models.

Old 07-10-2008, 11:14 AM
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Default RE: RCM Ultra Sport 60 mods

Mike,

Great web site!!!
Thanks..hope it helps you in your build. Be sure to send
me a picture of your completed US60 and I will put it up
on the web page.

- Did you use 1/8" music wire as recommended for the elevators?
Yes.

- Where did you get the music wire, LHS, Hardware store?
The piece of 1/8th was something I had laying around. The 5/32 for the
main gear came from the LHS. The 1/8th can be bent with hand tools
but I ended up getting a K&S wire bender for the main gear. It was a good investment.

I saw your model came out heavier than expected.

- How do you see that overweight affecting your model?
Not at all. The Ultra Sport carries the weight well.

- How is your vertical climb performance?

I am getting used to have unlimited vertical in my models.
Vertical is quite good but not unlimited. Who really needs unlimited
vertical anyway? Mine goes up as high as I need it to. I used a rather
old but reliable OS61SF. Any modern 61 would out run it.

Keep weight reasonable...use a good strong 61 and you will have
a great performing plane.

The first US60 I flew belonged to a friend and he had a Tower 75
on his. It was an almost perfect combo and is what I would get
were I building another US60 today. But since the Tower 75 is
no longer available and is looking like will never be available again
some other choice would have to be made.

Your 61FX should be just fine.
Old 07-10-2008, 11:41 AM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: XTOL

1. Split elevator is an unnecessary complication. The elevator joiner is small
and can be bent with hand tools. Thats how I did mine.
And I would say that a DEPS system is simply the only way to go for elevator control. Easier setup, more precise and less prone to flutter. YMMV, but I would never install a single elevator pushrod on any 60 sized aerobatic model.

Just my $0.02.


Mark
Old 07-10-2008, 11:49 AM
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Default RE: RCM Ultra Sport 60 mods

Why do you say the TH-75 was al almost perfect combo?

Happens that I do have a NIB TH-75 that I was keeping for a propped Direct Connect F-18 kit. I just lubricated it well when I received it three years ago.

Now you got me thinking about which engine to put in the nose of this model.

Yes, I will be sending you some pictures of the build and final model for your gallery.
Old 07-10-2008, 11:49 AM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: mmattockx


ORIGINAL: XTOL

1. Split elevator is an unnecessary complication. The elevator joiner is small
and can be bent with hand tools. Thats how I did mine.
And I would say that a DEPS system is simply the only way to go for elevator control. Easier setup, more precise and less prone to flutter. YMMV, but I would never install a single elevator pushrod on any 60 sized aerobatic model.

Just my $0.02.


Mark
Perhaps...but on the Ultra Sport its simply not necessary.
Old 07-10-2008, 11:53 AM
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Default RE: RCM Ultra Sport 60 mods

Mark,

What is DEPS? Is it Dual....what?

Yes, I can take your $0.02

Pedro
Old 07-10-2008, 11:54 AM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: prgonzalez

Why do you say the TH-75 was al almost perfect combo?

Happens that I do have a NIB TH-75 that I was keeping for a propped Direct Connect F-18 kit. I just lubricated it well when I received it three years ago.

Now you got me thinking about which engine to put in the nose of this model.

Yes, I will be sending you some pictures of the build and final model for your gallery.
Well your TH-75 would be a better fit for the DC F-18.

The only time I wished for a little more power on my US60 was in
knife edge. Thats where the extra from a 75 would help.

Use the 75 in the F-18. Use the 61FX for the US. Best choices for
both planes.

Wish I could get a TH-75. They have been out of stock for
almost a year now. I wanted one for a Sig King Kobra I was
planning to build.
Old 07-10-2008, 12:03 PM
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Default RE: RCM Ultra Sport 60 mods

...
The only time I wished for a little more power on my US60 was in
knife edge. Thats where the extra from a 75 would help.
...
I hear you about the engines. Who knows when the TH-75 will be available again.

Well, I extended the rudder by 3/8". Hope it helps in KE.
Old 07-10-2008, 12:39 PM
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Default RE: RCM Ultra Sport 60 mods

Mike there has one of the most beautiful builds of this plane I have ever seen and the US 60 was originally designed with the wire between halves and on every plane I have flown they work fine. if it was a substantially larger plane it might be worth dual servos for each half.
Old 07-10-2008, 02:25 PM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: carlosponti

Mike there has one of the most beautiful builds of this plane I have ever seen and the US 60 was originally designed with the wire between halves and on every plane I have flown they work fine. if it was a substantially larger plane it might be worth dual servos for each half.
Carlos,

Thanks for your input. Music wire will be.



Old 07-10-2008, 03:06 PM
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Default RE: RCM Ultra Sport 60 mods

DEPS = Dual elevator pushrod system. It is one of the best ways to control split elevators (either that or dual servos). The problem with using the music wire as recommended in the plans is that unless you get the holes in each half drilled exactly the same on each side (which will require some meticulous work) you will end up with roll coupling on elevator input. The Ultra Sport can be made to be a decent precision flyer if set up correctly. I would agree with the previous comment recommending using a dual pushrod system as opposed to joining the elevator halves. You can either buy a pref-fab kit like the one sold by Central Hobbies, or make one yourself.

Edited due to temporary dyslexia
Old 07-10-2008, 03:48 PM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: mjfrederick

DEPS = Dual elevator pushrod system. It is one of the best ways to control split elevators (either that or dual servos). The problem with using the music wire as recommended in the plans is that unless you get the holes in each half drilled exactly the same on each side (which will require some meticulous work) you will end up with roll coupling on elevator input. The Ultra Sport can be made to be a decent precision flyer if set up correctly. I would agree with the previous comment recommending using a dual pushrod system as opposed to joining the elevator halves. You can either buy a pref-fab kit like the one sold by Central Hobbies, or make one yourself.

Edited due to temporary dyslexia
MJ,

Thanks for educating me. So many acronyms nowadays.

In building, my goal is always build the next model better than any previous one. So, I will give it a thought while I build the rest of the plane.

At this moment, I have built the stab, elevator halves, rudder, and cut ribs. I will complete the fin today. Then I will start building the wings. So, I still have a couple of weeks for solving the elevator control dilema.

I still have not decided on the hinges. I have three options: pins, flats, and common CA hinges.

Old 07-10-2008, 04:08 PM
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Default RE: RCM Ultra Sport 60 mods

Here is the Central Hobbies DEPS:

http://www.centralhobbies.com/contro...age/deps1.html

Also, search on DEPS in the Pattern Forum and you will find lots of info on them and how to set them up. The pattern guys all either use DEPS or dual servos if they need the tail weight, nothing else works as well for precision and adjustability. If you are striving to make it better, this is the only choice out there.


Mark
Old 07-11-2008, 07:42 PM
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Default RE: RCM Ultra Sport 60 mods

I built mine from a kit. It has an early ASP 61 in the nose and it works just fine, plenty of grunt. I used Spring Air 104 (?) 3/16HD pneumatics in it. They work great, I've only flown it a few times. I stopped flying as I finally got up to it's capabilitys. The club guru flew it for me a coupla times and he loved it. My flights were just a little too nervous. But it flew perfectly. I used a wire for the tail, not 2 servos or wires.

Mark Shuman
Old 07-13-2008, 12:08 PM
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Default RE: RCM Ultra Sport 60 mods

one of the finest builders on this website (user name: 8178) uses the DEPS method on his pattern planes. i plan to do the same.

david
Old 07-18-2008, 08:23 PM
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Default RE: RCM Ultra Sport 60 mods

I thought about posting some pics of the building...

Any one interested?
Old 07-19-2008, 10:32 AM
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Default RE: RCM Ultra Sport 60 mods


ORIGINAL: prgonzalez

I thought about posting some pics of the building...

Any one interested?
Of course...I've never seen an Ultra Sport (in any stage of
construction) that I didnt like...

I had so much fun scratch building my US60 I just might
scratch build a US1000 this winter. Either that or a 120
size Super Sportster. Its a toss up.

Just wish balsa trees would grow in Illinois...the US1000
takes a LOT of lumber.
Old 07-19-2008, 11:36 AM
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Default RE: RCM Ultra Sport 60 mods

OK...here we go...

Cutting all ribs...I had a second thought and decided to hollow some them...I am leaving 8 and 1 complete.

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Old 07-19-2008, 11:40 AM
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Default RE: RCM Ultra Sport 60 mods

Then stab, to save some weight, I decided to build it hollow too...

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Old 07-19-2008, 11:42 AM
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Default RE: RCM Ultra Sport 60 mods

Rudder is made of balsa playwood...I decided to increase it by 1/4"...

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Old 07-19-2008, 11:47 AM
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Default RE: RCM Ultra Sport 60 mods

Right wing...In this plane, like the idea of slotted LE and TE. So, I did the same..

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Old 07-19-2008, 11:48 AM
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Default RE: RCM Ultra Sport 60 mods

Ah... I will install the retracts in between ribs 4 and 5, not as originaly designed between 3 and 4.
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Old 07-19-2008, 11:51 AM
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Default RE: RCM Ultra Sport 60 mods

So... This is were I am at this time. I completed the central sheathing of right wing and I have mave the spars for the left wing. I will start construction of the left wing today.

I left rib 8 complete because it's where I will support the aileron servos. This model will have flaps to about 30% of original aileron. So, rib #8 is about half of remaining aileron. I also included some 1/4x1/4 stock for hinge support inside TE. Although, I am thinking that 25% flap might be sufficient. I need to think more on this before completing the sheating on the other side. That's why I started left wing to allow some more thinking time.

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