jrf

My Feedback: (551)

Box car:

I agree, it looks fatter, but it actually measures out about the same. I think the color scheme and the cowl that fits over the fuselage, rather than being built into it, makes it look that way. Beauty is in the eye of the beholder, and my eye likes the real Ultra Sport better also.

Jim

KaP2011

My Feedback: (17)

Ah, I see. I agree, not a good thing. Probably won't fly like an Ultra Sport, more like an Extra or a Cap.

jrf

My Feedback: (551)

First, my goal. I do not want to just test the Taipan and see how it does. I want it to be as close to an Ultra Sport as it can be. If that requires some easy changes, I will do them and tell you what I have done.

The instructions say to build the wing first. OK, but there have been two important changes in the wing of the Taipan vs the wing of the Ultra Sport.

1. The Ultra Sport has 2 degrees of dihedral (see my response to KaP2011 above) and the Taipan has none.
2. The Taipan main gear mounts position the wheels a couple of inches further aft than the main gear of the Ultra Sport.

Reducing the dihedral reduces the airplanes stability in upright flight and increases it's stability in inverted flight. One of the great things about the Ultra Sport is that it is equally smooth and stable in all attitudes. Reducing the dihedral would take some of that away. But it is easy to fix!

Sand 1/16" to 3/32" off the bottom corners of the wing joiner. You do not need to add anything to the top corners because the epoxy will fill that area when you install it. Glue the wings together using the rubber bands and clamp as they show in the instructions, then support the wing in a building cradle and put a weight on top to keep the top of the wing straight while the epoxy sets. The top should be straight across from tip to tip. It should have no dihedral in the top surface.

When the epoxy has set, fill the 1/8" gap in the bottom of the center joint with epoxy/microballoons.



Having the main gear that far back will make the airplane tend to nose over easily. But this fix is even easier and it will work for retracts or fixed gear. Just add a 1/4" hardwood or plywood spacer on top of the rear half of the gear mount. You may need to sand the vertical side of the rear mount a little to clear the retract or the fixed gear block. The second photo shows the gear after the spacer was added.



The only other change I made to the wing was to enlarge the servo holes and use full sized servos for the ailerons. But that is a personal choice and should not affect the way the airplane flies.

Jim

Twin_Flyer

My Feedback: (4)

jrf,
while everything you say makes sense, if the Taipan isn't built stock, you will never know how if flies as was designed. it may very well fly just fine.

Plus they don't call it an Ultra Sport clone, they describe it as "Inspired by classic pattern-style aerobatic aircraft, the Taipan from VQ is designed for precision aerobatics."

However, I may wait to see how yours flies with the changes to the wing before I start my build. Can't hurt!!

Bill S.

jrf

My Feedback: (551)

Bill:

You are right, I have a good idea how it will fly with the reduced dihedral, but I will never know for sure. That is not my goal. I want to see if the Taipan is, or can be, a worthy substitute for a kit or plans built Ultra Sport. In my opinion that would require that it be as close a copy as possible in the areas that affect it's flying characteristics. Changing the dihedral is certainly one of those.

They can not call it an Ultra Sport clone without Great Planes' lawyers getting all upset, but I have it on good authority that an Ultra Sport 60 kit was sent from LA to Viet Nam late last year.

I suspect that the box stock Taipan would fly pretty well. I will leave it to the magazine reviewers to let us know about that. But with differences like the dihedral and the main gear position, I am 100% sure that it will not fly or ground handle just like (or as well as) an Ultra Sport.

Jim

Twin_Flyer

My Feedback: (4)

Jim,
That makes sense, I have never owned a 60 size US, but rather the 1000 so I have no reference to compare.

I guess I will have to follow your build and see how it goes.

Thanks
Bill S.

RCKen

My Feedback: (9)

I'd be real interested in getting one and actually pulling the wing apart and see just how closely its structure resembles the Ultra Sport. By doing that you could get a good idea if they actually did copy a US to make this clone.

Ken

Super08

My Feedback: (2)

Speaking of the 1000 I was sizing up ground clearance for props on the plans. With the trike gear which I always thought looked so good on it the clearance is very tight. However if I go with a taildragger and use a set of 4" White Rose wheels I have it will give me 2" of clearance with the fuselage level and a 17x10 prop. The wheels are cnc'd aluminum and are very lightweight. They won't look oversized as a taildragger and are only 1" wide. They look the same as these Airman 5" wheels I have on another plane.

jrf

My Feedback: (551)

Ken:

The structure of the Taipan is 90% plywood, full of lightening holes. It is totally different than the all balsa structure of the Ultra Sport. When the Asian factories copy something, they build the outside the same as the sample, but they do the internal structure to suit the materials and tools they have available to them. Balsa and CA are very expensive in Asia and they need to build them fast, using jigs, lasers and wood glues. Not to mention that they have to build to a price.

The inside of the Taipan is very different than the inside of an Ultra Sport. The outside, however, is an almost perfect match. I call it a clone because the size, appearance and function are the same.

But if that characterization bothers you, I will stop saying it.

Jim

RCKen

My Feedback: (9)

Doesn't bother me at all to say it. I had a long talk about the plane with Mike Greenshields from Hobby People in Toledo.

Ken

RoyR

I don't know for sure, but I would think most ARFs have their own technique for building, which isn't like kits, but something they can do quickly and with less weight. But that's just my guess. I know the ARFs I have seen uncovered are made for lightness and seem to be much less strong than the kits. Also I remember from the earlier posts (I think on this thread) many people said they thought the Ultra flew best by being a bit heavy as compared to ARFs.
In fact Minnflyer made a "lite" version of the US and said this: "I never did actually weigh it, but I was noticeably lighter by feel. That said, I was not impressed with it. The Ultra Sport actually flies better with some EXTRA weight rather than trying to shave any off."
Of course, Ken you would know more about that project than I do, but just wondering if the lightness of the Tiapan will have an effect on the flying compared to the Ultra Sport kit.

RCKen

My Feedback: (9)

Mike (Minnflyer) and I had that conversation about the "lite" version of the Ultra Sport, which I got a chance to fly when I visited him, and we both agreed that the heavier plane actually flew better. There are many examples of planes that lighter isn't always better and the Ultra Sport is definitely one of those.

Ken

jrf

My Feedback: (551)

Hey guys, I just weighed the finished Taipan and in spite of what the box and the ads say, it is a few ounces heavier than an Ultra Sport 60. The final weight will have to wait until I finish adding tail weight, but it is looking like 7 3/4 pounds ready to fly.

Never trust the advertised weight of an ARF.

Jim

Twin_Flyer

My Feedback: (4)

Those wheels sure do look nice Super. Not having heard of the brands you mentioned I looked them up, wow, expensive!!

Considering the size of US 1000, a standard set of Dubro would get the job done, and I doubt the plane would even notice!

I had been flying mine with an old and tired OS 120 FS with the taildragger configuration, soon I will be re-powering mine with a Saito 150. Should liven it up a bit!

Im tempted to put a 30cc DLE in the nose, but don't want to cut into the bird and redo it so not going to happen.

Bill S.

Super08

My Feedback: (2)

Yes they are pricey and these will probably be the only ones in use on a small glow fuel plane. They are more intended for use in giant scale gas powered airframes. I just happened to have a set spare left over from a plane that I sold and kept the good wheels.

jrf

My Feedback: (551)

Today I finished mounting the engine, installing the fuel tank and cutting and mounting the cowl. All I have from that is just one minor item that should not directly affect flight characteristics. If you want to make the Taipan the best it can be, and you are using glow power, you might want to do this, but if you are just sport flying and don't spend a lot of time upside down, you might skip it.

This change affects the way the engine runs. If you are using glow power, mounted on its side, you will note that the fuel tank is mounted on top of the "battery floor" which puts the center of the fuel tank about 1/2" above the carburetor centerline, even with no padding under the tank. With the tank in that position, if you are using an un-pumped engine and you tune the engine for upright flight, it will tend to run leaner when the airplane is upside down or pulling negative Gs.

In the Ultra Sport the tank is mounted so that the center of the tank lines up with the center of the carburetor, in order to eliminate that problem.

Modern engines, running with tank pressure, do not seem to suffer much from this, so leaving it that way may be just fine. But I am kind of a fanatic about consistent, reliable engine runs, so I removed the "battery floor" from the fuselage and lowered the hole in the firewall so that I could mount the tank level with the centerline of the carb.The tank is held in position with foam "rubber" all the way around.

The first photo shows the engine mounted on the provided mount. Note that the side of the mount is only 1/16" from the side of the fuselage.
The second photo shows the cowl and muffler cutouts, and the 3" spinner I substituted for the smaller one provided in the kit.
The third photo shows the "battery floor" which sits about 3/4" above the bottom of the tank compartment.
The fourth photo shows the fuel tank, lowered and secured in foam all the way around.



Tomorrow I will mount the tail surfaces and again try to restore them to Ultra Sport specs.

Jim

Twin_Flyer

My Feedback: (4)

The engine mounted on it side always looks better then one upright. I only mounted one inverted once, and it was always a problem...

Good idea about the battery floor!

Bill S.

jrf

My Feedback: (551)

The Taipan's rudder is controlled by a standard servo using pull - pull cables. Although this is not the setup used in the Ultra Sport, it is a good setup and I will not change it. There is one problem though. The exit holes in the rear of the fuselage are about 4 inches too far aft for the cables to make a straight run. You can only move the exit holes 3 1/2" forward because of a lightening hole in the right side of the fuselage, but that, plus crossing the cables inside the fuselage (they are plastic coated to eliminate radio interference) makes them a lot closer to straight.

The Taipan has three servo mounting holes for the elevator servo(s) in the rear of the fuselage. There is one full size mounting hole on the left side and two mini size holes, one on each side. The mini servo holes are staggered, both horizontally and vertically. Clearly they are giving the builder the option of using one standard servo or two minis.

The Ultra Sport uses one standard size servo, driving both elevators which are connected by a music wire joiner. The advantage of this setup is that, if the joiner is stiff enough, the movement of the elevators is always matched. Using two servos driving separate elevators must have some advantage because I see it a lot on giant scale and 3D airplanes, but I don't know what the advantage would be for a 60 size sport pattern model.

The major disadvantage of the two servo setup is getting the travel of the two servos matched. If they are not precisely matched, when you pull up, or push down, you will also get some roll. If the arrangement of the servos and your transmitter programming is perfect, it is possible to precisely match the travel of the two servos. Unfortunately, the way the Taipan is set up, with the staggered servos,with different length pushrods reaching the control horns at different angles, I'm pretty sure it can't be done. (If you disagree, email me and I can go into details.)

There is a small problem with the single elevator servo option on the Taipan, though. They do not provide an elevator joiner, and the elevators are factory hinged to the stabilizer. Well, that's not a big deal. Cut the elevator free. Bend a 3 1/4" long joiner with 1" legs from 1/8" music wire (that is definitely stiff enough), install the joiner and re-hinge the elevators.



On to installing the radio and balancing.I am hoping to fly it on Tuesday.

Jim

jrf

My Feedback: (551)

Radio installation went well. No problems until I tried to balance the airplane. The recommended balance point is 30 - 33% of the chord. About right for a sport pattern plane. The recommended control throws, though, are quite low. I set them up as low rates and added 30% to each surface as high rate.

When it came time to balance the airplane, I was amazed that it took 4 1/2 ounces of lead in the tail. Not liking that idea, I moved my 5 cell receiver battery as far into the tail as possible.



It sits in the space directly behind the single elevator servo, which is the space where the two mini servos would go it you chose that option. With the battery there, I did not have to add any lead in the tail.

Surprisingly, it took a full ounce of lead in the left wingtip for lateral balance.

The final, ready to fly, dry weight is 7 pounds 11 ounces. That is a few ounces above the 7 to 7 1/2 pound weight range specified for the Ultra Sport 60 in the original article in RCM.

OK, do I have a good stand-in for an Ultra Sport 60? Is the Taipan something you can throw together to fly while you are finishing up that Ultra Sport kit-built masterpiece? I hope to find out tomorrow.

Jim

Twin_Flyer

My Feedback: (4)

Jim,
Can't tell from that pic but is there any foam or some sort of padding around that battery? Just wondering if there is room for it.

Good luck and good weather for your maiden flight!!

Bill S.

jrf

My Feedback: (551)

Bill:

The battery is wrapped with Hitec's foam receiver wrapper and padded with foam rubber on both ends. I had to take out part of the former behind the servo but I replaced it with the cross brace that you see over the battery.

Jim

ochsnm00

Interesting post. Have you run that GMS in anything else?

jrf

My Feedback: (551)

Ochsnm00:

I ran it in a seaplane and again in a trainer. It likes low nitro fuel. Did not run well on 15%, but it is a pu**y cat on 5%.

Jim

jrf

My Feedback: (551)

RECAP:
The Ultra Sport has been in constant production for 25 years and clearly its flight characteristics have a lot to do with that. The Ultra Sport is groovy, flies on rails, feels locked-in, has neutral stability and it is fast and smooth and forgiving. It is not a 3D flyer or a fun fly machine, but for sport pattern type flying, there is nothing better. Unfortunately it is only available as a kit, and it is an old style kit that involves carving and sanding those nice curves.

Now Hobby People has introduced an ARF called the Taipan that looks like an Ultra Sport clone. Unfortunately, in it's stock form, it will not fly like an Ultra Sport. I must admit that I have not flown a stock Taipan, but there are four major differences between the Ultra Sport and the Taipan that will alter the Taipans flight and ground handling characteristics. Maybe someone else will try it stock to see how much it is affected.

To make the Taipan into a true substitute for an Ultra Sport, I needed to do the following easy mods: (Detailed in my earlier posts.)

1. Hobby People took the dihedral out of the wing. I put it back in.
2. The Taipan has a "battery support floor" in the tank compartment. I removed that so that the center of the tank would line up with the carburetor.
3. The Taipan's main gear mounts put the wheels too far back. A simple spacer cures that.
4. Using the dual elevator servo option on the Taipan would not allow the travel of the two elevators to be properly matched. I used the single servo option, which requires making and installing a music wire joiner.

The stock Taipan, with less dihedral and mis-matched elevators will not sustain level flight or respond accurately to control inputs. It will have a tendency to roll off one way or the other in upright flight or when pulling or pushing elevator. The higher tank mounting will make the engine run leaner under negative Gs than it does under positive Gs. And the main wheels sitting too far back will give the airplane a tendency to nose over.

FLYING:
I spent this morning flying my modified Taipan, and it does indeed fly like an Ultra Sport. It is groovy, stable, smooth, fast, forgiving and all of the things I said above about the Ultra Sport. It is very fast at full throttle, but it will slow down to walking speed for landings. It will not tip stall. It will fly hands off from one end of the field to the other, upright or inverted, without turning off course. My engine runs are consistent and it does not want to nose over while taxiing. It does big round loops and linear rolls. It makes me look like a better pilot than I really am.

It is a bit nose heavy with the recommended CG and the only trimming I had to do was a few clicks of up elevator to compensate. I liked the higher rates that I set in the last post better than the lower recommended rates.

I am going to call this project a rousing success, and I will have a ball with my Taipan until the covering comes off, which won't be very long for that shelf paper. Then I will recover it and fly the heck out of it some more.

Thanks to RCKen and all of the Ultra Sport Brotherhood for letting me post this project here. I hope it has been helpful, or at least entertaining.

Jim

ochsnm00

Congrats on the successful maiden and thanks for a great thread. It sounds like the Taipan is a keeper. I hope it stays on the market for awhile.