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World Models Spot-On 120

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Old 07-18-2007, 07:14 AM
  #101
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Default RE: World Models Spot-On 120

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ORIGINAL: riot3d
Congratulations on your maiden flight. What size of prop are you using, and which 120? The SF, NC, AC or the SC?
Adrian
Thanks! I'm using an APC 16-8. I just found the box and it's an "SC". Turns at about 8700 RPM. I have a 16-10 I might try. Might be too much prop though.

I'll try the snaps using different throws. There aren't any snaps in Intermediate but it's always good to practice!

Thanks.......Mark
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Old 07-18-2007, 11:02 AM
  #102
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Default RE: World Models Spot-On 120

Try a 15x10 or 15x12. Just stay between 8400-8700 rpm and you will be fine.

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Old 07-18-2007, 05:29 PM
  #103
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ORIGINAL: piroflip2

hi riot3d.

that is one beautiful model.
may I ask what the build/covering quality is like?
my Groovy 90 f3a was the worst built artf that I have ever seen, absolutly dreadful.
I bought it to break into f3a comps but could not complete a practice session without something cracking, splitting or falling off.
In the end I got an Infinity X, different class.

regards piroflip

First of all, I have to admit the plane is not perfect. You can tell from my build thread some area needs to be improved on, with the covering being one of them, and I have reflected my concern to World Models. In addition, they need to change to a lighter engine mount. As a matter of fact, I'm toying with the idea of switching to a Budd mount. Along with a nose ring and bracket, it weighs in at 6.3 oz, as compared to World's 8.6 oz .

However, the plane performs real well under the circumstances. If World can improve on those area, I'm confident that it will be an even better flying plane.
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Old 07-22-2007, 01:33 PM
  #104
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Default RE: World Models Spot-On 120

An other flight report on the Spot On 120.

Made two more flights today and I wanted to expand on my ealier report.

Knifedge flight.

This plane doesn't know when you put it on it's side. Knifedge flight at half throttle or more takes very little rudder to maintain. If I fly the length of the field (approx. 1000ft.) it will just barely pull to the gear. Meaning that for any manuver requiring knifedge in a contest you will not need to cross control or do any radio mixing to maintain straight flight.

My favorite:

Slow Roll.

This has been my favorite manuver for many years. I judge the capabilitys of a plane based off of how well it slow rolls or how easy it is to make it slow roll. Today I flew the prettiest slow roll I've flown in 10 years (been out of pattern for 10 years). With the lack of roll coupling with rudder input, this plane flys a fast, medium or slow roll just beautifully. The plane still takes more down elevator inverted than I like but I'm still adjusting the stab incedence and CG.

Wing over, Hammerhead.

This one has me stumped so far. I've tried it with the engine at idal and half trottle and it doesn't like to pivot. The only conclusion is it needs more rudder travel. I'll report more on this when I've tried more thow.

I left IMAC because I missed flying a plane that flew like a pattern plane. This plane is exactly what I was looking for. Man, I've missed pattern.

At this point I have only one real complaint about the Spot On 120. After only three flights, the blue trim on the right wingtip started coming off. You would think that if World Models can design such wonderful flying models, they could at least put decent covering on them. I will have to recover the wingtips with Ultracote. This is after spending much time going over the covering with an iron before I started assembly. This stuff they put on just does not stick.

Bob
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Old 07-22-2007, 09:50 PM
  #105
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Default RE: World Models Spot-On 120

I flew mine again today. I'm still having to move the CG back. I moved the batteries from under the elevator/throttle area, to the under the rudder servo area. Still flies nose heavy. I then added 1/2 oz of lead to the tail and still needs more. I'll just keep adding more weight and then see where the CG is. Then I think I'll cut open the bottom and move the battery back in the lower turtle deck and remove the weight. Do these pattern planes get funny as you move the CG back? The Imac planes take a lot of aft CG before they become an issue on landings. All I'm looking for is slight pressure on Elev to hold inverted flight. Should I be playing with the stab incidence at this point also?

Thanks.......Mark
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Old 07-22-2007, 10:09 PM
  #106
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Default RE: World Models Spot-On 120

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ORIGINAL: OnTheEdge

I flew mine again today. I'm still having to move the CG back. I moved the batteries from under the elevator/throttle area, to the under the rudder servo area. Still flies nose heavy. I then added 1/2 oz of lead to the tail and still needs more. I'll just keep adding more weight and then see where the CG is. Then I think I'll cut open the bottom and move the battery back in the lower turtle deck and remove the weight. Do these pattern planes get funny as you move the CG back? The Imac planes take a lot of aft CG before they become an issue on landings. All I'm looking for is slight pressure on Elev to hold inverted flight. Should I be playing with the stab incidence at this point also?

Thanks.......Mark
As long as you do it at a small increment at a time it will be ok. Generally, modern pattern plane with long tail are very stable. As a matter of fact, I'm doing the same thing. I'm going to keep adding tail weight until the down ele trim will cause only slight down ele pressure to hold inverted flight. Then, I will add positive incidence to the stab to make it flush with the down ele trim. If you are nose heavy, by just changing the stab incidence will not work.

Adrian
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Old 07-24-2007, 10:20 PM
  #107
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Default RE: World Models Spot-On 120

Which ever one of us finds the correct CG, please post it hear. I now have 2 1/4 oz of lead on the tail and it still needs sufficient elevator to fly inverted. I actually ran out of weights!
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Old 07-25-2007, 08:05 AM
  #108
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Default RE: World Models Spot-On 120

I figured the MAC for the Spot On and found that the CG given by the manual is good for quick checks. When I initially checked the CG the plane needed 1 oz. of weight in the tail. I used a Dubro tail wheel rather than the one included in the plane. The Dubro was a ¼ oz. heavier than the original. I mounted ¾ oz forward of the tail wheel for the first flight. I’ve since added another ½ oz. and it seems to need more. When I finally get the CG right I’ll report it.

In my case the need to add up trim for level flight while upright is the indicator that I’m using to determine correct CG location. I’ve currently go 7 clicks of up trim in the elevator. This sounds like a lot but I’ve reduced the trim step on the transmitter. Each click of trim is half of a normal click. Of course, up trim is the same as using down trim when inverted and at this time it requires a lot of down elevator when inverted.

If I get the covering repaired, I’ll fly again this weekend and give a report of my findings.

Bob
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Old 07-30-2007, 09:23 AM
  #109
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Default RE: World Models Spot-On 120

Any new CG specs? I haven't flown mine since last week.
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Old 09-07-2007, 06:44 AM
  #110
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Default RE: World Models Spot-On 120

Has anybody flown this with an OS 160 ? Would the OS fit in this plane?
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Old 09-07-2007, 12:37 PM
  #111
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Default RE: World Models Spot-On 120

Watch your weight on the 160, the plane is already nose heavy to start with.
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Old 09-08-2007, 11:08 AM
  #112
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Default RE: World Models Spot-On 120

Is there any other place to order the Spot On 120 other than AirBorne-Models?
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Old 09-08-2007, 11:38 AM
  #113
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Default RE: World Models Spot-On 120


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ORIGINAL: Zippi

Is there any other place to order the Spot On 120 other than AirBorne-Models?
Airborne Models is the US distributor for World Models, owned or owned by World Models too, sort of the same company. You can also order the plane from your LHS and keep everybody happy and in business...
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Old 09-08-2007, 05:00 PM
  #114
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Default RE: World Models Spot-On 120

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ORIGINAL: Zippi

Is there any other place to order the Spot On 120 other than AirBorne-Models?
If you're a current NSRCA member, Airborne will extend a 10% discount to you.
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Old 11-25-2007, 07:02 AM
  #115
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Default RE: World Models Spot-On 120

Thanks to everyone for their comments on this thread. Looks like the perfect plane for someone like me, who loves pattern flying but no longer competes (now flying pattern just for the fun of it). I have a couple of comments, which I hope will be taken constructively and not insult - definitely not my intention to tread on any toes.

Firstly, the wing and stab should be at the same angle of incidence if you intend for the plane to fly upright and inverted in a similar manner. You will then have to experiment with the CG to achieve that neutral and balanced feeling with minimal trim change. If you need up-trim to fly upright and down-trim (forward stick) to fly inverted, then your CG is too far forward. Apologies if I'm preaching to the converted, but there seems to be some confusion about this.

It's been my experience that kit manufacturers always have conservative (forward) CG settings, which require compensating up-trim / neg stab incidence for level flight. When the plane is inverted the excess nose-weight still wants to drag the nose down, but now the stab trim is wrong for level flight - you need to compensate with down elevator. I've flown a 3m IMAC Katana that was set 0-0 and needed no up-trim nor forward stick in transitioning from upright to inverted. Sure made the sequence a lot easier. The downside is that the plane will be a *little* trickier to land, because there is no reason for the nose to drop when you throttle back. No problem - you have an elevator, and should be prepared to push a little nose-down during a landing sequence. I've got an Extra 300 that can be landed hands-off due to this effect, where the nose stays where its pointed, and the rate of decent is controlled by the throttle. Any full-size pilots out there will know this technique very well.

Secondly, if this plane is turning out nose-heavy, why not mount exposed servos in the tail? I know many scoff that this looks ugly and adds drag, but the aileron servos are exposed, so why the fear? I hate adding weight to planes, so why not let the servos be the tail ballast?

Finally, I don't understand the concern about various engines being "overkill". I've never flown an aerobatic plane that was overpowered. Some correctly mentioned THROTTLE MANAGEMENT. When you drive you car to the flying field, you rarely floor-it, so why the "firewall the throttle" mentality when flying? If you only need 75% throttle to maintain speed in the up-lines, why go to 100%? I fly with throttle management all the time, and I really love that no matter how much trouble I get into in the vertical, I've always got the power to pull out, especially after a mult-snap. The 3D flyers understand this need for pull-out power VERY well.

Anyhow, this has been a great thread and I will be submitting my order for a Spot On as soon as time permits. If anyone finds a good CG point please advise the thread. Power to all of you, and happy patterning. Any lead on how to order the Naruke canopy? The stock canopy looks a little weird.
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Old 11-25-2007, 01:19 PM
  #116
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Default RE: World Models Spot-On 120

I saw it hanging on the ceiling at Radar models in Hong Kong. Looked pretty nice. Actually, it looked better in person than in the pictures. Nice size and lines. I'm sure it will do fine. But that canopy has to go.
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Old 11-25-2007, 03:35 PM
  #117
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Default RE: World Models Spot-On 120


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ORIGINAL: Straight Up

Firstly, the wing and stab should be at the same angle of incidence if you intend for the plane to fly upright and inverted in a similar manner. You will then have to experiment with the CG to achieve that neutral and balanced feeling with minimal trim change. If you need up-trim to fly upright and down-trim (forward stick) to fly inverted, then your CG is too far forward. Apologies if I'm preaching to the converted, but there seems to be some confusion about this.

> Mine is nose heavy due to the 140L, that's why I relocated the tank to the cg point. Unfortunately, you do not have much room to play with the battery location.


Secondly, if this plane is turning out nose-heavy, why not mount exposed servos in the tail? I know many scoff that this looks ugly and adds drag, but the aileron servos are exposed, so why the fear? I hate adding weight to planes, so why not let the servos be the tail ballast?

> If you check one of the pix that I have posted with my friend's crashed Spot-On, you can tell the tail section is pretty hollow, making it tough to mount two servos on the tail. Besides, adding two servos is like adding "dead Weight" as you mentioned. If you used the correct power plant, you should be ale to balance the plane correctly.



Finally, I don't understand the concern about various engines being "overkill". I've never flown an aerobatic plane that was overpowered. Some correctly mentioned THROTTLE MANAGEMENT. When you drive you car to the flying field, you rarely floor-it, so why the "firewall the throttle" mentality when flying? If you only need 75% throttle to maintain speed in the up-lines, why go to 100%? I fly with throttle management all the time, and I really love that no matter how much trouble I get into in the vertical, I've always got the power to pull out, especially after a mult-snap. The 3D flyers understand this need for pull-out power VERY well.

> Again, the plane is designed for a 120 sized engine. Since I do not own any more 120s, I decided to use a 140L and pay the price of being nose heavy and have to keep playing with the cg, it is not a matter of having too much or too little power. Don't forget, bigger engine not only generates more power, but also more torque thus generates more vibration, especially with a 4 stroke. End results, more punishment to the airframe and your airborne packs.


Anyhow, this has been a great thread and I will be submitting my order for a Spot On as soon as time permits. If anyone finds a good CG point please advise the thread. Power to all of you, and happy patterning. Any lead on how to order the Naruke canopy? The stock canopy looks a little weird.

> Good luck to yours, I'm sure you will enjoy building and flying it. Now the WC is over, I will start flying the Spot-On again and may be able to shed more light on the cg. The Naruke canopy came with my Astral XX, I just happened to have two spare ones. You may be able to obtain one from BVM, X-treme's US distributor.


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Old 12-12-2007, 10:19 PM
  #118
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Default RE: World Models Spot-On 120

riot3d,

I've enjoyed following your build and fly thread on the Spot-On 120. Just got mine and starting to assemble it. Planning to use a YS110S (mostly because I have one). From your posts, and others, I believe it will not be a bad choice. I don't fly FAI (only back up to adv this coming year after a 15 yr layoff) so the 110 should be adequate and maybe keep the weight down a bit.

After looking the kit over, I have a few areas of concern where I'd appreciate your comment. The first is the horiz stab mount system with the tube and incidence adjusters. How sturdy is it and did you find the incidence adjustment wortwhile? Have you played with the stab adjustment? Where did you finally set it? Has vibration loosened it?

That brings me to my next issue - the virba-damp type engine mount. Does it adequately control vibrations? My experience with a similar mount supplied on an Icepoint was poor (albiet with a YS160DZ) and I ended up replacing it with the YS mount. Do you think the supplied mount is adequate for the YS110 ?

With respect to the CG, do you know what %MAC ( or distance from the center LE ) you finally settled on? Or at least where you are now ? And where you think you'll end up? I usuall try to start around 30%MAC and end up around 32% - that seems to suit my flying style, but it can vary considerably from plane to plane.

Thanks in advance for your advice. And thanks again for the great build thread.

Jack

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Old 12-13-2007, 03:51 AM
  #119
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Default RE: World Models Spot-On 120

Hi Jack,

Welcome back to pattern. To answer your questions:-

> so the 110 should be adequate and maybe keep the weight down a bit

In theory, the 110 should have enough power, as long as you don't have too many vertical maneuvers. Not only it will keeps the weight down, but you also don't have to relocate the fuel tank to the cg point. However, the weight between a 140 Sport and a 110 is about 6 oz difference. Therefore, be careful to ensure you have the correct cg.


> The first is the horiz stab mount system with the tube and incidence adjusters. How sturdy is it and did you find the incidence adjustment wortwhile?

The actual adjustment mechanism was a bit flimsy. When they drilled the openings at the factory, they sometime oversized the holes making it real easy to stripped the threads. Be careful when you install the adjustment screws.


> Have you played with the stab adjustment? Where did you finally set it? Has vibration loosened it?

Yes, you do need to fine tuned the stab incidence after you have settled with the correct cg. As long as you do not over-tighten the adjustment screws, you will be ok.


> the virba-damp type engine mount. Does it adequately control vibrations? My experience with a similar mount supplied on an Icepoint was poor (albiet with a YS160DZ) and I ended up replacing it with the YS mount. Do you think the supplied mount is adequate for the YS110 ?

I only have about 30 flights on the plane. So far, I do not have any issue with the mount. However, only time will tell whether that affects the longevity of the airborne packs. Since I have had no experience on the Icepoint mount, I can not compare it with the World's mount. I do not foresee any problem on your 110. Especially, I am using a 140L.


> With respect to the CG, do you know what %MAC ( or distance from the center LE ) you finally settled on?

I have not yet settle on the final cg point. Between attending the Worlds and gathering parts for my X-treme ProLine, I kind of neglected the Spot-On for the past few months. However, I'm planning to fly it again starting this Friday to get a better feel of the plane and will report again.


> where you think you'll end up? I usuall try to start around 30%MAC and end up around 32% - that seems to suit my flying style, but it can vary considerably from plane to plane.

As you mentioned, it's a very personal thing. Some like it slight nose heavy, while tail heavy suite others. I like to hold very slight down ele while inverted.

Hope this helps. If you need more info feel free to contact me.

Adrian
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Old 12-14-2007, 05:19 PM
  #120
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Default RE: World Models Spot-On 120

Hey, what about an O.S. 120 Ax on this bird?

I don't know why, but I always thought a 2 stroke engine was the best choice to a pattern aicraft, but all you guys are using 4 stroke!!!


In fact, I need to start on the pattern flight, because I want to refining my fingers (too much 3D currently).

So, I was wondering to get this plane, but seems the engine choice for it is a little hard.

And taking the message, can somebody indicate to me a good place where I can learn about pattern maneuver?????

Thank you guys!!!!
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Old 12-14-2007, 08:05 PM
  #121
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Default RE: World Models Spot-On 120

Here's the US pattern site. You can find lots of stuff there. Also, links to the AMA pattern rules and sequences. Not sure if Brazil follows the same or similar rules.

On the left there is a section entitled "Getting Started"

http://www.nsrca.org/


Hope this helps.......Mark
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Old 12-16-2007, 02:52 AM
  #122
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Default RE: World Models Spot-On 120

Guys, several have asked, but I still don't see an answer to the OS120AX question! I'm in the same position. I have a OS120 and YS 110, both with hyde soft mounts. I also have a flex header/pipe for the YS which fits the canister nicely. Will be my first time with a canister or tuned pipe on the OS. But let me get this straight, I have to pull the pipe apart everytime I'm done flying?
Thanks
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Old 12-17-2007, 10:01 AM
  #123
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Default RE: World Models Spot-On 120

djr1007
you should get an extra power with 120ax compared to ys 110. I've seen spot on 120 plane and its heavy compared to groovy 90. You should try YS 110s same weight with old ys 110, but 25% more power. 110s reads 9500-9600rpm 14x11 30% coolpower. The only problem with 120ax is 100 grams heavier and would make the plane a little bit nose heavy. Just add some counter weight at the tail.
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Old 12-17-2007, 08:19 PM
  #124
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New plane Mark? Happy Holidays
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Old 12-19-2007, 10:42 PM
  #125
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New plane Mark? Happy Holidays
New plane for one contest. Had a great time.

Merry Christmas to you and the family.

......Mark
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