Hey guys,

This is gonna be a long post, but I have a bunch of questions.


Just wanted to get some input from the gang on here regarding some basic (and in some cases advanced) questions about pattern/pattern planes. Are alot of these answers "because thats the way its been, thats what everyone else runs, etc"?
Just wanna get a grasp on what I have gotten myself into by getting a pattern plane.....

1. Why are fiberglass/carbon fiber fuses the norm? Are they close in weight/strength to built up balsa/ply? It seems the time involved in laying up the fuse vs building a wood one seems pretty close. Is it the stability/rigidity of the glass fuse staying straighter over time vs the habit of balsa expanding/warping due to humidity changes? How much stress is put on the airframe during the various schedules? I know they dont do full throttle blenders or "gut-wrenching" maneuvers. What is the repairability off the fuse if it gets dinged up. Even a minor repair could throw you over the 11lb weight limit, which would disqualify you at a high level of competition. At that point, do you pitch the fuse and start over??


2. Why are sheeted foam wings the norm? Is there a significant strength gain by going that route (less flexing under load on such a thin wing)? Is it for aerodynamic purposes (no ribs protruding thru the covering, etc). Would a built up balsa wing be lighter and just as strong? (assuming a fixed gear scenerio)

3. The trend for going back to fixed gear? Is this beacuse of the weight savings in Carbon gear? Tired of messing with the linkage on retracts, and/or downgrades for gear failure on landing? Less electrical load on the battery for a stuck retract servo?

4. How does fixed gear alter the balance and flight characteristics of the same airframe? Is the drag increase noticable causing a pitch to the belly?


5. Widebody designs vs narrow fuse designs. Advantages, disadvantages, etc. I'll assume the widebodies are for slower downlines, but how much negative influence is the increase in drag for the rest of the pattern? Do you have to increase the engine power to handle the increase in drag, volume/weight?


6. Why are gas engines not widely used in pattern planes? Is this because a gasser cannot make the 11lb weight limit without major modifications? Or is this one of those "well, people have always used glow, and that's just the way its been and will be to be competitive" items. Gas powerplants are becoming smaller,lighter and more powerful that in the past, and would have to be cheaper to run over the course of a season.


7. Two stroke glow vs 4 stroke glow? What do you run, and why do you run it? I know most of the two strokes are at a small torque disadvantage than the 4 strokes, but have more overall power at the top end. What are pros/cons of each.....


8. Are the YS engines worth the cost/headaches involved with running one? I know they put out a ton of power, but it seems like you have to have two per plane, one in the airframe while the other is being serviced. Is that a true statement? How much does it cost to "factory service" an engine, and how often do you have to do it?

9. Nitro content in glow fuel? Whats your prefered nitro amount, and can you see a dramatic increase or decrease in performance by changing nitro and/or oil type/content? How many compete with the FAI fuel, and how does it perform vs regular glow (needle adajustibility, power, torque, cooling, etc).

10. How much control throw do you have on your surfaces, and do you use dual rates?


11. How "fast" do you fly your pattern? How fast should the plane be "presented" to the judges?


12. Your favorite airframe (current or past design). Strongpoints and weaknesses of it.


Any other input or comments you guys care to add, please feel free.

Let me state this right up front, I am NOT trying to start a series of flamewars on the above topics, I am just looking to compile a bunch of usable information so we can use as a reference on here. I'm also trying to answer a bunch of questions that I have thought up over the last few months. Given the proven abilities of the competitors on here, the info would be very valuable.


Thanks,

Steve

Hey...
You may want to post this q on the NSRCA board.

The current competitive planes..Patriots.Oly's. Prophecies and the Focus are all wood.

Try NSRCA.org and join the mailing list..it's free.

Have fun.

Thanks Steve! I am getting started too. I hope some of our "in the know" pilots will help out...


Regards
Bill

Hmm...I'll try to answer these as truthfully as I can.

1. Why are fiberglass fuselages the norm?

A: Ease of manufacturing. It's really that simple. There are a lot of variables involving using wood, including density and weight. Also a wood fuselage is a lot more work, and hard to get straight unless you know what you're doing. For production, glass, or carbon/kevlar, is much easier. It is also a tad bit lighter than wood, and a bit more rigid. I'm generalizing here, but that's it without typing a whole page. The flight loads aren't too much.

2. Why are sheeted foam wings the norm?

A: Again, ease of assembly. It's easier to get a straight wing, and get it fast. A PROPER built up wing when utilizing carbon spars and proper assembly is actually lighter AND stronger. But it's a lot of work and it's not easy. Pattern wings are very intolerant to warps no matter how slight.

3. Why use fixed gear?

A: Lots of reasons and depends on who you ask. They are much less of a headache than retracts, and on the newer draggier designs, retracts aren't an advantage. Why expose yourself to downgrades and failures if you don't have to? You still have to trim them in, but they don't have a noticable adverse effect on wide body designs.

4. How does fixed gear alter the balance and flight characteristics of the same airframe? Is the drag increase noticable causing a pitch to the belly?

A: No. It does create more drag than retracts, but that is desirable with the newer sequences.

5. Widebody designs vs narrow fuse designs. Advantages, disadvantages, etc. I'll assume the widebodies are for slower downlines, but how much negative influence is the increase in drag for the rest of the pattern? Do you have to increase the engine power to handle the increase in drag, volume/weight?

A: Everything is a trade off. There is no perfect design, no matter how much a manufacturer would want to tell you differently. if you widen the fuse, you pay for it with crosswind penetration. If you narrow the fuse, it tracks like an arrow, but it's fast and knife edge flight suffers somewhat. There are some very good compromises out there however. Many modern designs are making the best of both worlds. The best thing is to choose a plane that suits your flying style and practice with it. Then the negative effects are corrected. And you can never have too much power =)

6. Why are gas engines not widely used in pattern planes? Is this because a gasser cannot make the 11lb weight limit without major modifications? Or is this one of those "well, people have always used glow, and that's just the way its been and will be to be competitive" items. Gas powerplants are becoming smaller,lighter and more powerful that in the past, and would have to be cheaper to run over the course of a season.

A: Gas engines are not as powerful ounce for ounce as a glow engine. With an 11 lb weight limit, it's a chore for the common guy to get enough power under the cowl and make the limit. However it has been done, and it will be done more in the future. Technology is the key here. Right now it's just easier to slap in a glow engine and go.

7. Two stroke glow vs 4 stroke glow? What do you run, and why do you run it? I know most of the two strokes are at a small torque disadvantage than the 4 strokes, but have more overall power at the top end. What are pros/cons of each.....


A: 2 stroke glow all the way baby!!! Seriously, I chose to go this way because it has less moving parts, it's more reliable (for me) and the power is outstanding. The power curve isn't as smooth as a 4 stroke, but a little practice and it's not an issue. Some guys swear by 4 strokes, so it's a preference thing. Use what you're comfortable with here.

8. Are the YS engines worth the cost/headaches involved with running one? I know they put out a ton of power, but it seems like you have to have two per plane, one in the airframe while the other is being serviced. Is that a true statement? How much does it cost to "factory service" an engine, and how often do you have to do it?

A: See answer #7. Heh. To me they're a huge headache and a garaunteed dead stick. There are 2 kinds of people that run YS engines: those that never have a problem, and those that have nothing BUT problems. It's a good engine IF you know how to operate it properly. They aren't very tolerant to abuse though. The jury is still out on the DZ however, it's too early to tell. So far it looks very good.

9. Nitro content in glow fuel? Whats your prefered nitro amount, and can you see a dramatic increase or decrease in performance by changing nitro and/or oil type/content? How many compete with the FAI fuel, and how does it perform vs regular glow (needle adajustibility, power, torque, cooling, etc).

A: I use 10-15% nitro in my 2 strokes. yes I can feel a difference between 10 and 15. I don't have the need to go higher. Some guys run 30% in the YS 4 strokes. YS engines like nitro. Nobody I know of uses FAI fuel nowadays.

10. How much control throw do you have on your surfaces, and do you use dual rates?

A: This varies greatly with design and the sequence you're flying. For an FAI pilot, he needs LOTS of throw available, whereas a sportsman pilot is hurting himself. The actual amount varies from one plane to the next. It's generally fine tuned in flight and the variables can include prop, speed flown, fuel, balance point, etc. I use 3 different rates on every surface and 3 flight conditions. And that's very basic.....

11. How "fast" do you fly your pattern? How fast should the plane be "presented" to the judges?

A: As fast as it needs to be smooth without busting the box. Seriously, if you can fly slowly and under complete control, slower flight scores better. It's also a lot easier to control positioning in the box. If you have more time and more room to set up a maneuver, it's going to be better.

12. Your favorite airframe (current or past design). Strongpoints and weaknesses of it.

A: It doesn't exist =P No, I like the Typhoon 2000 for a lot of reasons. It's wood, and I build my own planes from wood. easy to change things I don't like. With fiberglass, it's a little harder. It's an extremely stable design, and therein lies it's weakness as well. It doesn't snap and spin very well. It does it, just not cleanly. I have hacked and changed this thing until it's not a Typhoon 2000 anymore. Everything is different now. But it flies like a zillion dollar eurokit, and nobody knows how little I really spent =) Best looking? ZN alliance, or G Naruke's G 320.

I know a lot of that was vague and short and generalized, but I could write a book on this stuff, and half the people out there would tell me I'm wrong. Heh. Pattern is ever changing and evolving, and that's one of the big attractions. you never stop learning, and you never stop changing your mind about stuff. if you think you know everything, you're in deep trouble because you just stopped learning.

But those are my opinions, take them for what you will. i'm sure someone with more experience than me can add more, or tell me I'm wrong =)

Mike Hester
District 3 AVP, NSRCA

Thanks Mike,

Thats the kind of input I am looking for. And, I'm sure there will be a million different opinions from a million people.

I guess the fixed gear can also save some big $$$ on props as well.

Keep the input coming.

Steve

How does one "trim in" a fixed gear?? I have flown fixed gear but never bothered to trim them. Just got them in as straight as I could.

Basically you get them as straight as you can =P

Some people mount them at wierd angles and wonder why they have trim problems. They are like little airfoils. Mount it at 0 deg to the airflow and leave it unless it throws your trim out. Then you have to actively trim it....however most don't do this.

Mike

Let me take a kick at this, most of my answers will probably be similar to MHester's

1. Ease is probably the #1 reason, I can quickly get 3 planes exactly the same without much effort (once the mold is done). A built up fuse is probably more rigid torsionally, and absorbs vibration better. Composite fuses are pretty simple to fix (a small crack), but if they are crashed they are usually a write off, while you may be able to fix a built up fuse.

2. Again simplicity, easy and fast to make, lightweight cheap etc etc. Kinda the KISS principle on that one.

3. They are both the same weight in reality. Fixed gear is nicer since you dont need a stand (unless you are a one peice wing) to assemble your model. They both have their problems and it boils down to personal choice for most people. One thing, if you have any inclination of an off field landing use retracts.

4. You wont notice them hanging down there, I would debate that they do not increase the drag any noticable amount.

5. Widebody.....it helps with knife edge but thats about it, looks bigger in the air allowing you to fly further out at times I suppose. More drag, again that is all design dependant but in most cases I would say you would never notice it, the wings/stab/propellor have a larger influence on downline drag than anything else. A properly designed wide fuselage will handle crosswinds well, that was a major difference between the Vector and the Evolis that I have flown, the Vector was flat sided and did not like a strong cross, the Evolis has roundish sides and could care less about a crosswind.

6. I think it is basically a lack of any availablility, there really are not any gassers that would compare to the current motors without modifications of planes. Produce a drop in power plant with the correct power/weight requirements and I bet they start popping up.

7. Can of worms this one is I run the YS 140DZ, it is far superior to the 140L, and from the two strokes I have flown there is no comparison. Its got the power of the 2 strokes with the awesome power band of the 4 stroke, what more can you ask for. Reliability? Hasnt missed a beat all summer.

8. If you run them properly you are fine, most people just run them too lean in my experience which causes problems. I would send mine in once a year for a $20 ring and never had any real trouble with them. IMO the 4-strokes do have an advantage for pattern.

9. I run 25%, everything works well on that...

10. Only as much as is required to do what I need to do. I use conditions on my 9ZAP, so I have one for normal flight, one for spins and one for snaps. In normal flight I try to set it up so that I have as little throw as possible to do the manuvers with as close to linear expo as possible. This is really a preference thing for most guys.

11. Well in FAI you only have 10 minutes from start time to wheels down time, I try to shoot for about 9-9.5 minutes as that seems to be a good pace for the flight this includes the start up time flight time is maybe 8-8.5 minutes.

12. I am flying a pair of Evolis XXL's right now, its working good and an improvment for the FAI stuff over the Vectors that I used to fly. Its good in rolling and snapping manuvers, but I cannot get the spins right, that might be just me I dont know. I also have ZN's latest the Enigma, its an Evolis on roids, with a much bigger fuse and some more minor changes too many to list here. I have hopes that it will improve upon an already excellent airplane in the Evolis.

Steve,

Does Dean ever come out to CLRC and fly his pattern planes? Have you decided on what engine you want to run on your airplane? Does your airplane have the same wings as the Phenom? I'm at school right now, but I can talk some when I get home.

Steve,

Ditto what Mike and the others have said, but let me just say if you are on a budget, and want to fly pattern do not overlook the OS 160 or the Super Tigre G2300. I know someone who has the OS, and I have the ST.

These engines require a hopper tank set-up or a fuel pump to work well in a pattern plane, but they are almost bullet proof, and you can treat them like your .40 sport engine.

Good Luck
Greg

Chad,

How on earth do you manage to squeeze in all that flying into 10 minutes?!? That must be a little hard to do, did you have any trouble doing it when you first started FAI?

Great input Chad and Greg. It's very interesting to hear how a worlds competitor can pick apart even the best airframe hehe.


Ryan,

Dean hasnt flown any of his pattern stuff at CLRC, but he did have one of his new smardgz fuses in his truck one morning. It was definately a thing of beauty. I dont think our field is set up well at all for pattern, given the road/power line at the east end, and the house on the west end of the runway approach. We are really having to watch ourselves on overflying the road and the far treeline to keep some new neighbors pacified. I think the curving hump of our runway also keeps Dean's pattern hardware away from our field.

As for the wings on my plane, I was told that they were prototypes for the Phenom, by the builder of the Phenom. I cannot verify if they are the "production" version. Who knows, maybe I got the wings that fly as good as paperclips LOLOL.

I still havent figured out an engine choice yet. I've been traveling for work, and have had a massive project load, so I havent been able to play with the planes much.

Ill keep you posted.

Steve

Hi Ryan

Its actually not too bad, it just seems to work out that if you fly a comfortable speed to give a brief pause between manuvers then the timing just kinda works out. You can get into problems if you fly very far out and at slow speed. I know that I am pacing the flight good for me when I feel that I am just barely comfortable with the pace of the flight, if I start to feel rushed then I know I am either too fast or too close (usually too close), if I feel like the time between manuvers is taking forever then I usually bring the plane in a little.

The first few times you fly the FAI sequence its probably going to feel quite busy, but then it gets managable. Its kinda hard to explain, but I find that the timing just falls into place.