This is not a kit question, but since I'm doing so many mods I thought it would be okay to ask in the Kit Forum.

Just bought a Tiger 60 ARF and a Saito FA-100. I have several mods I want to do, but wanted to run them by others who are familiar with this plane before proceeding.

List of mods:
1) Taildragger conversion - considering carbon fiber gear with fiberglass wheel pants - not using stock mains in the wings.
2) Enlarging rudder and maybe elevator. Some say it's not necessary, other that it helps on more advanced flying.
3) Inverted engine installation with pitts style muffler.
4) Larger fuel tank with possibly moving to CG and relocating radio gear and battery to original fuel compartment. This might help with the CG issues. ( I know when I put together my Eagle 2 ARF, I tested servo and battery placement before locating the servo tray. Glad I did, since I moved servo tray as far forward as possible and put battery nd radio just behind fuel tank. All this and still have to add a weighted spinner to just balance. The Tiger ARF has the servo tray already mounted)
5) Fabricate either a balsa or fiberglass cowl to make it pretty, just cut it off at the firewall and start there new. Not sure about cooling issues, but thought if I have air intake in the front and left the bottom of the cowl pretty open it should do fine.

Any comments, pros or cons, tips or tricks?

Thanks!

Your mods sound good. I would also add to use two aileron servos. The torque rods to the ailerons flex and will flutter. I have seen this happen on a couple of Tigers.

On the cooling issue incorporate a scoop about the size of the frontal area of the cylinder. Don't forget to leave an exit twice the size of the inlet and you should be fine.

Just my .02
DEG

A larger rudder might make it knife edge, but I would probably want a torqier rudder servo. Other then that, it sounds good!

Thanks for your feedback. This model has dual aileron servos, so I'm good there.

Well you guys are much more positive then the guys at my local hobby shop. I went in today to start doing some recon for parts to do all these mods and talked to a couple guys and told them what I was up to. They are telling me that inverting the motor and moving the tank away from being a close to the engine is asking for trouble. Inverting will make it more difficult to tune and easier to flood, though it will work. Moving the tank will cause leaning problems when doing vertical climbs and you should always keep the tank as close to the engine as possible (unless you have a fuel pump as in the case of some of the gas engines).

So now I'm all discouraged! Does all that he is saying true. Has anyone out there done these kinds of changes and had all these problems? Or is he just being overly cautious with me?

Thanks

I am building a Tiger II right now. I went with a larger fuel tank to keep it close to the engine. I got one that would mold with a little heat. That way you can extend it a little further back maybe use you power pack to set the CG without having to add any weight. Think light... ... If you invert the engine I would add a remote glow igniter to make starting a little safer. Those props are hell on a manicure. Depending on how much larger you want to make your rudder just strip the one that came stock with your plane. Then get a piece of stock The same thickness x 3/4 in, more or less You get my drift though. I would epoxy it, just thin it a little since there will be a good deal of stress on the new extension. My tiger called for one servo for the ailerons, but I may use one for each side. I have just started the right wing so we will see here before to long. I say go for it. If the guys at the hobby shop have a problem with it then they need to stick with r/c cars.... maybe they can comprehend that a little better. You know !QUOT!giver some gas!QUOT! left turn right turn... wow what excitement...l .. sorry I guess that was not so nice... [&o]

crazy4rc
I have been running inverted engines for a while. A few Saito's an an OS hanno. The Hanno is pumped so there is no problem with it.

The Saito's do seem to sag a bit at the top of a long vertical line, but my fuel lines were at 14" from spray bar to rear of tank. I fixed this by installing a Cline regulator. They ran like a top after installing the regulator.

On an inverted engine you have to have the low end set correctly for it to run right. When you shut the engine down after a flight pull the throttle and trim lever all the way back and burp the tank. This will keep the carb from flooding. Spend the time to get both Hi and Lo needles set and you won't even know the engine is inverted.

I haven't had any trouble hooking and unhooking the glow starter on mine. You get used to where it is and the motion it takes to do it. The Saito glow plug angles back so that helps keeping you hand away from the prop. To me it is no different than an upright or side mounted engine....RESPECT the PROP.

DEG

Thanks iflyrc24,

That's more like it and more in line with what I was thinking. I'm not a mechanical or technical idiot, so I think I can handle this. What do you mean by 'burp the tank'? I was worried a little about the flooding issue, that makes since, due to the fact it's an updraft carb which will now be down drafted with the possibility of flooding.

I'm also not familiar with the Cline regulator, I'll have to look around on the net to find out more. Thanks for your feedback!

C4RC
When you run a Cline or Iron Bay regulator you have a check valve in your pressure line to the tank that holds the pressure in. With the engine running you will have 2 to 12 psi in the fuel tank. When you shut the engine down the pressure will still be in the tank so you need to burp it. To do this you just pull the pressure line loose and let it go psssst. This way the fuel tank won't be trying to feed the carb with the engine off. Remember you will have the throttle and trim all the way back with the engine off. You also have to do this if you have a YS engine.

Do a search here on RCU for Cline Regulator and Iron Bay regulator. You will get all the info you need to make your decision. They are both the same principal, the Iron bay seems to be better made and a little cheaper. I have used the Cline with good results but I think I am going to try an Iron Bay the next time.

[link=http://www.ironbaymodelcompany.com/index.html]Iron Bay [/link]
[link=http://www.billsroom.com]Cline[/link]
DEG

Hows the Tiger going? I have 1 under the tree, hehe. I will be going for the taildragger and a slight stretch on rudder and elevator.
My goal is to make it a solid workhorse for 4 season all surface flying.

Has any1 done wing mods to a tiger? Like taking a rib out of each side?

I was told by a person at a show representing Goldberg that taking one rib out would make it perforem even better. It was too late for me to modify the two that I was working on, but I would like to try it in the future. Let me know how it works for you.

Built the tiger 60 kit a year ago.
Quite frankly, I prefer the trike landing gear vs. the tail dragger. Tail dragger just doesnt look right on this plane, but thats a personal choice. Guy at club has tail dragger club and he seems to be Ok with it. I added Dual strut nose gear on mine, which perhaps is one very big advantage to a tail dragger, you get to avoid the dreaded nose gear blues. Rudder mod sounds Ok, but its hard to imagine it could be even larger. My kit built very tail heavy ( others had same experience, pehaps arf is different), had to add a lot of weight to nose. I like the larger tank idea but would suggest you try to locate it as far forward as possible, assuming your Arf needs nose weight. I have an inverted OS 70II Surpass 4 stroke on mine. No problems with inverted engine (with stock tank and placement). In fact, that engine was made for that plane. A OS91 would make this plane perhaps even better. I added a dubro fuel filler cap on my fuel tank cover ( in hindsight I'd have added it to the side, fuel cover blows with engine thrust). FG cowl seems like overkill, since you could "ply-in" the cowl for more of an inclosed look, but once again, if it adds nose weight and you need nose weight, why not.
Look forward to seeing the finished product. Good luck, This is one great plane.

Wayne
.

I've been so busy that the mods are going to turn into my winter project now. When I get it done I will post pictures, maybe even progress pictures if anyone is interested....

I have done several mods to my Tiger 60. I power with a OS 61 fx. With this setup the plane is very tail heavy. I didn't want to add addl weight so I moved everything forward - battery, servos receiver. I even cut off part of the rudder support on the top of the fuse - useless dead weight anyway. The firewall needs to be beefed for the trike gear. the fuse is weak behind the wing bolts.

Very cool design! How did you create it?

OK since you asked about the ARF, here is a recipe for success. Use your Saito 100, make it a taildragger with light weight gear, install a 16oz Dubro fuel tank (yes it fits), install 2 Hitec 225 servos in the tail (yes tail) which eliminates the rod flex, leave the elevator alone (it is fine), enlarge the rudder if you want by about 25% (more like a Cap or Extra style (look at the H9 Advance 40). Now don't worry about the cg, it should fall about 1/2" to 3/4" past the rear part of the cg range (trust me on this). Now how do I know this? Well I have one setup basically just like this. Mine has a ST .90 2c, servos in the tail, 16oz tank and balances 1" behind the rear cg mark. It flies GREAT!!!!! These are very tolerant of cg location. I have a NIB T60 ARf yet to finish with a .91 4c, the one I'm flying now was crashed into the back of my wife's Pathfinder! The damage was minimal (plane and truck) and the owner gave it to me instead of fixing it. I did the above mods and am flying the daylights out of it. BTW, it will knife edge as long as you want and I have not done the rudder yet!

Thanks. The tiger is first covered in cub yellow. Using a pair of scissors I cut out the tiger stripes and iron them on. Do a search in google for images of tiger stripes to get a ideas for stripe patterns.

.......OK since you asked about the ARF, here is a recipe for success..........

Hey, thanks for the feedback! I took some of your advice. I decided not to modify the elevator, but still enlarges the rudder. I too was thinking of placing the servos in the tail section, but wanted to wait until I was further along so I could check the balance before comitting. Since you have done it, I went ahead and put the elevator servo in the rear, but kept the larger (more torque - and would not fit - I went with JR digital servos) servo up front with a pull-pull system for the rudder. Hopefully this will aid in final balancing. So happends I did pick up a 16 oz tank which is going in just forward of the CG over the wing. Since the servo tray and a bulkhead was already in the way of exact CG, I had to comprimise on the location a little.

I'm working on improving my Tiger 60 ARF's performance for Sportsman Pattern use...

The main problems I am seeing:

1) it loves to roll when you kick the rudder trying to do the stall turn. Its very hard yto get through the stall turn without ending up 90 deg out. Experimenting with technique of making it pivot witout rolling are getting me nowhere... (best result has been with a crosswind and being able to do the up line with the plane canted 20 deg to compensate)

2) It noses up with power... or drops the nose when inverted. I've got the CG at 5.25 inches from the leading edge now... (thats 43% MAC) The plane is stable... but on the edge of getting touchy to elevator trim (I don't think I can go any further back)

The trike landing gear helps a lot in getting good take-off and landing scores. I've got a piece of fuel tube on each side of the nosewheel and pressed in HARD when installing the 2nd wheel collar... the drag on the noswehll makes it easy to have the plane sit in place on the runway at idle. (if it doesn't that's a downgrade on the takeoff)

I have experienced similar flying characteristics, but mine is the older kit with the semi symetrical airfoil and I assume yours is the symetrical version. The older type of wing will behave as you describe. I also have a new foam wing with the symetrical airfoil, but have not flown with it yet. My COG is 4.75"

The rudder I find to be almost ineffective at slow or no speed. I am not a designer. I just don't get the tail feathers. I do enjoy flying the Tiger60, but I cant imagine using this airplane as a pattern craft. I have a Swallow ex 90 for that. I tend to use the Tiger as a "warm up plane" when I'm feelin rusty. Although this winter I've been finding it challenging too!!! - Not enough air time.

Try adjusting the down angle of the engine just a tad, it may help. Mine flies very well and does not do this. The rudder itself IS kind of stupid and small but works for now. I can see a Cap/Extra style rudder coming for mine soon though.

I finally have some modification pictures for your viewing pleasure! I still have not complete the project and flown it yet, but I'm VERY close and hope to be in the air within a couple weeks.

I have a web site with photo galleries of my planes and projects. Here is the link to the Tiger:
[link=http://www.georgescott.com/RCHobby/Tiger60/]Tiger 60 Modifications with photos[/link]

Here is one picture of my custom built cowl over the inverted Satio 100 with Pitts muffler:
AND
Here's one of the tail feather modifications, massive rudder and doubled built-up elevator: