Some SD 33% Yak HP/ DA85 questions

[Show871]

This is my first gasser and I am stoked! I am sure I will have numerous goon questions as I build the plane and your help is much appreciated! I just got my 33% HP version with the firewall pre-installed. Q#1, I am mounting my DA 85, and was wondering what the pre installed firewall angle is, or what off set from center to place my template? Also, for the height of the motor, is there an easy way to do this????? inline with center of wing????? Thanks 871

[mikel7099]

	Quote: Originally Posted by Show871
	This is my first gasser and I am stoked! I am sure I will have numerous goon questions as I build the plane and your help is much appreciated! I just got my 33% HP version with the firewall pre-installed. Q#1, I am mounting my DA 85, and was wondering what the pre installed firewall angle is, or what off set from center to place my template? Also, for the height of the motor, is there an easy way to do this????? inline with center of wing????? Thanks 871

I'm sure someone will tell me i am wrong but here is how i did mine. I bought the standard version not the HP version, OK ready? I found my center point of my firewall top to bottom, side to side, were the two lines met that was the center of my firewall. Then i measured each side of the engine box to find the difference in length between the two sides and that would be your offset for right thrust(i believe mine was a 1/4"). Now were the two lines meet on my firewall i measure that distance i calculated and marked it that was my new firewall center point for the engine. I put my engine's template, center point over the firewalls that i just made and then marked the holes drilled out and mounted. Mine flies great no problems and trims and surfaces are centered and the spinner measured evenly all the way around the cowl. Hope this helps and don't confuse you more. Pics maybe hard to see.

[mikel7099]

Here is a link to TBM's website on the left of the page and down a little are the instructions with pics that may help you or make it easier to understand. I believe it was page 14 http://www.troybuiltmodels.com/AMY54.htm

[luv2flyguy]

If you go to http://aerobaticmodels.com they have the templates that you can download and print out for your plane. Hope this helps.

[Show871]

Thanks for the tips, That template is MONEY!!!!!!!871

[Show871]

Ok, using the template on the FW, and lining up the DA 85, it looks like I will have to cut into the box "floor" to get the carb to allow the engine to "push in" and mount up. Is it ok, and "normal" to cut into thte floor, or should I be considering other options??????THANKS 871

[luv2flyguy]

Hey 871- Make sure that template is correct. I downloaded it and then measured the DA-85 and it seems that the holes are off. I just made my own, it's really not that hard to do. Just measure the bolt holes and transfer it on a piece of poster paper.

[Show871]

Thanks, I will double check the holes! Is it normal to cut into the box floor (that the tank sits on) to get a carb to fully clear when sliding in the motor?????

[bill hatcher]

Show871 yes its normal to have to cut a half moon shape in the engine box floor for the carb. Make sure when you print it out that the size is correct. It should measure the demention on the templete. You may have to resize your printer to make it right but it is the perfect fit when you get it done.

[Show871]

Thanks for the heads up! I was just scared to cut into the floor! Also, I noticed on my DA85 it would be much simpler for throttle servo h/u to rotate the carb around 180deg. Is this cool??????THANKS871

[Show871]

Where are you guys running the cg????? The manual says 7.25" from the front of the wing, but states there is huge variation in what works best. I am currently tail heavy @ 7.25" Got this thing almost ready to go and it is trick as hell!

[LawnJockey]

I have found that my Yak flies great slightly tail heavy. I have a 3W 80Xi in mine.

[Jaketab]

Caution,

A member my RC club had the older version of the SD 33% Yak with DA-85 combo. He used a template and the hub/spinner came out way off center in relationship to the center of the cowl.
I would recommend not relying on template. Stand the fuse upright on the tail and secure it to a bench with a cord or strap. Temporary mount the engine on the motor box with rubber bands. Cut the cowl rough so it will fit over the engine and in place. Center the engine hub in the middle of the cowl opening and mark where the bolt holes are. Remove cowl and engine. Now draw a rectangle to the exact dimensions of the bolt hole pattern. Use this to double check and mark the precise points to drill the bolt holes.

Jaketab

[Yakov]

Any of you guys that have/had the SD/AM/TOC# 33% Yak ever use only one servo per aileron?

I have one of the ARC versions and I am about to cover the wing and thought I might just go with one Hitec HS5955 per wing. If you did do this mod did you just use the inboard or outboard servo mounting position or did you build a new servo bay in thre middle of the wing? Did you stiffen the ailerons at all by sheeting or whatever? Any issues with the aileron flexing with just one servo.

I would like to go to one serrvo for weight savings as well as the ease of setup with just one. I mean 333oz should be enough for a plane this size. I woud think 666oz would just be overkill and an un-neccessary drain on the flight battery.

Also contemplating mounting 2 x HS5955TG in the tail for rudder. Anyone done that?

I am installing a DA 85 with JTEC oversized Pitts muffler and still deciding on a prop.

Here is the colour scheme I am finishing mine in......

[mikel7099]

	Quote: Originally Posted by Yakov
	Any of you guys that have/had the SD/AM/TOC# 33% Yak ever use only one servo per aileron? I have one of the ARC versions and I am about to cover the wing and thought I might just go with one Hitec HS5955 per wing. If you did do this mod did you just use the inboard or outboard servo mounting position or did you build a new servo bay in thre middle of the wing? Did you stiffen the ailerons at all by sheeting or whatever? Any issues with the aileron flexing with just one servo. I would like to go to one serrvo for weight savings as well as the ease of setup with just one. I mean 333oz should be enough for a plane this size. I woud think 666oz would just be overkill and an un-neccessary drain on the flight battery. Also contemplating mounting 2 x HS5955TG in the tail for rudder. Anyone done that? I am installing a DA 85 with JTEC oversized Pitts muffler and still deciding on a prop. Here is the colour scheme I am finishing mine in......

I dont think i would run 1 servo per aileron these surfaces are big on this Yak. One rudder servo is not enough IMO, i use two 5955's I also replied and have pics in the other post!!