Extreme Flight Yak 54 88" and DA85 - Stump Puller!

[wc524]

Well guys I've just started on a project to get my DA85 on my Yak. I have seen many guys run the DA50, and it just wasn't enough. Call me crazy and tell me all about how the wing loading is going to be high....I'm not hearing it. There are several guys in the UK running the DA 50 on a smoke system and there will be little to no difference in overall weight comparing the DA50 w/smoke vs my DA85 and pipe.
DA50 on Pitts muffler with smoke (Hovers at 3/4 throttle).

YouTube - Extreme Flight Yak 54 88" Prop...

I want to hover a little above idle; better fuel economy...Yeh I'm sick.


I spoke with Curtis from Extreme Flight and most of the people who have tried to get the Yak with the 85 could not get it to balance with the standard pitts muffler, so I am solving this issue by putting in a MTW RE3 tuned pipe and putting the batteries in the rear of the hatch area. To top it all off I'll be running a Mejzlik 3-Blade 24x12W to get all that power and help smooth out with the tendancies of a tuned pipe.

I will get pictures on later of the fiberglass and carbon reinforcement we have already done for the motorbox to stiffen it up for the 85.

You motto with this build is "You never know how sweet something can be until you try."You know I'm going to have video of this once it's done! And maybe I can convert some people to put an 85 in their next Yak.

Extreme Flight takes no responsibility for this build and does not recommend a DA85 for this airframe. I just wanted to be different.

[BoneDoc]

Good luck Parker, this should be fun .

[Jim Woodward]

Parker - we are here to support you!! Go forth young man and conquer!!
Jim

[cjcyclesrc]

Should be interesting. That motor and pipe would yank a 110" around. That would make for some wicked power to weight. Have you thought about moving the rudder servo to the tail also. I can't wait to see some videos of it.

[danielph]

SHWEET! I don't think that you're crazy. Power is awesome, and that setup'll be great!

[wc524]

I have thought about moving the rudder to make it a direct push-pull style. I will check the CG after the pipe and header are installed to see if this will be needed. These wings are huge and I'm not really worried about wing loading. This Yak floats like no tomorrow.

[BoneDoc]

Although since you're going to go with 85 and RE3, the question that begs to be asked is: why not go with 110" instead?

[wc524]

	Quote:
	Parker - we are here to support you!! Go forth young man and conquer!! Jim

Thanks Jim. Missed you in Land O' Lakes last weekend!

	Quote: Originally Posted by bonedoc
	why not go with 110" instead?

Because I'm going to run the DA-100L on Pipes with smoke on that.

Also got the 88" already and Just figured the DA85 would be a great choice since it fits this airframe and is a little over 1lb heavier than a DA50 (less weight than a full smoke system 16oz tank, smoke pump, battery for pump, tubing, etc)

....Plus I'll be getting about 20 more lbs of thrust. Roughly 50lbs of thrust in a 19lb plane! I like that 2.63:1 power to weight

[bodywerks]

Seems like a waste to me, but it should be interesting for sure. Too much power can be a bad thing - lots of power is fine, but there is a breaking point. Not to mention that the 85 will shake that plane apart in probably about 10 flights. the prop it swings is 1/3 the wingspan! The 85 likes larger planes with a 100" wing or larger. The larger wing is a HUGE vibration dampener. Good luck!

[cjcyclesrc]

Bodywerks,

Have you had an 88"? I bet it will stand up to the shake. They are built very strong. I saw a guy that forgot to tighten his wing bolts slam one from about 10' and all it did was bend the landing gear, crack the cowl, and break his prop. The 88's landing gear should help some on the ground. It has a nice flex to it and is tall enough for prop clearance.

[wc524]

	Quote: Originally Posted by bodywerks
	Seems like a waste to me, but it should be interesting for sure. Too much power can be a bad thing - lots of power is fine, but there is a breaking point. Not to mention that the 85 will shake that plane apart in probably about 10 flights. the prop it swings is 1/3 the wingspan! The 85 likes larger planes with a 100" wing or larger. The larger wing is a HUGE vibration dampener. Good luck!

We're all entitiled to our opinion, but I think the DA85 is right at home in this airframe. As for the motor box it's been wrapped in a layer of glass and carbon reinforced, so it's plenty strong and still very light. I will limit my left thumb's movement on this bird don't worry.

If nothing else it will be a testament of the toughness of Extreme Flight's airframe. I'm looking forward to it.

	Quote: Originally Posted by wc524
	To top it all off I'll be running a Mejzlik 3-Blade 24x12W

I know people who ran the MVVS and 366GT motors with a 24" prop, so no worries about clearance here, plus I love the way a 3-Blade looks and pulls. I will make sure everything vibration related will balanced as best it can and taken into consideration. No plans on this airframe shaking itself apart any more than a DA50

[BTerry]

#1, this will be awesome. The weight will be similar to a 50cc on a canister as you say.

#2, you probably will want to beef up the wing tube.

#3, full throttle is for UPLINES ONLY.

[BoneDoc]

Again, this hobby won't move anywhere if there weren't people who defy the naysayers. Good luck with your endeavor and let us know how it feels...

... oh ya, we need VIDEO as well .

[wc524]

	Quote: Originally Posted by bonedoc
	Again, this hobby won't move anywhere if there weren't people who defy the naysayers. Good luck with your endeavor and let us know how it feels...oh ya, we need VIDEO as well

You got it! Video on Maiden.

	Quote: Originally Posted by BTerry
	#1, this will be awesome. The weight will be similar to a 50cc on a canister as you say. #2, you probably will want to beef up the wing tube. #3, full throttle is for UPLINES ONLY.

Thanks for your kind words Terry. Love the Avatar!

The wing tube is Carbon, so it will be plenty strong. I have seen people put more G's on this plane than I plan on putting it through. I like keeping my airframes, not ragging them out.

I will get some pics tonight after work of the modifications.

[tom222]

This is a great idea. I used to have a DL 50 in my extra, changed it to an MVVS 58 to increase the wing loading and power. A friend of mine flies his 88 YAK on a 58 too. I found it too floaty on the 50cc, its much better on the 58 and I'm sure would be magic on the DA 85.

Its great to see the wings bend in flat out KE circuits, thats an experience you just wont get unless your plane is stupidly overpowered or a bit floppy!

Heres a vid:

YouTube - windy practice

Thomas