flat spin

Well with the bolt mod and those servos you are probably looking at an extra 16 to 17 g's which all the way down there is probably the equvelent to 3oz up front. THe yellow strip is ok anyway so don't worry about that.

I have to say though, a freind of mine who bought the 68" Yak put those servos on the tail of his 68 and when we flew his it felt totally different to mine, i mean it was ok but it did not feel nearly as connected as mine. The linkages were all spot on so it definitley wasn't that. It wasn't as pronounced on the Ailerons though?

I personally think that the high end Hitec stuff is as good as anything you can buy but although you can get quite high powered and quick metal gear servos on the cheaper end you do compromise a lot on the centering, slop an precision.

wgeffon

My Feedback: (4)

Your fine.
That is just about where mine is. I think I am a tiny bit aft of that and my plane flies on the noseheavy side.
Go fly and see what you think and make adjustments from there.
Noseheavy or tailheavy isnt something you can determine without flying the plane.
You may be near one end of the range in the manual but until you fly you wont really know.

The numbers in the manual a VERY conservative. Chris feels that you should get it close, go fly and adjust it to your liking.
Dont get stressed because you feel your not in the range provided. The plane is not going to be un-flyable with a very aft CG. It will just exhibit some tail heavy tendencies. (not lockng in to snaps, Climbing while inverted... etc)

You have to remember that there isnt a lot of guesswork on this plane. Everyone of us is putting their servos in the same spot, Mounting the motor in the same spot etc.. Any weight differences between my motor, my servos etc.. and someone else's wont make that much of a difference.


Bottom line:
Dont get hung up over a number in the manual.
GO FLY IT!

SAL98

My Feedback: (6)

Hey Wayne. I have a question regarding your throw used for Imac sequences. Is it normal with a 3D setup to have to use 10-15% as a low rate setting in your transmitter if your using 100%-140% for 3D rates of 45-50 degrees? I have always had to use amounts this low to have a really smooth feel. And I still use about 35% expo. I'm wondering if this is really killing my resolution.

bodywerks

My Feedback: (4)

My CG is similar to yours. I am using the CH pipe, have no weight adding features aft of the CG, and my 4800 lion has to hang halfway off the front of the engine box and my 2400 is just behind the first former and I am ballancing at 7 1/8, if not slightly aft. I will have to do some inverted and knifedge flight to see what I nned from there...

Mudsurfer1234

Maidening my yak within like 2 hours if weather stays the way it is. can't wait!


Scott

Dave763

My Feedback: (1)

Scott good luck with the first flights. Let us know how it go's. I am still waiting for my DA[&o] I got most of it done, except for that. I ordered it 6 weeks ago. The guys at Toledo say it's gonna be 2 or 3 more weeks. Glad I got my order in before they raised the price. Now it's $595[X(]

coche

My Feedback: (4)

Scott.... good luck! and dont worry, this plane loves to fly! you wont have any problem! just calm your nervs, relax, and enjoy!!!

basmntdweller

My Feedback: (9)

I knew I forgot something in Toledo! I forgot to stop by and say hi to DrScoles. Watching his heli-fireworks DVD, he's near the top of my hero list
I hope to maiden my Yak one day this week as well. It's all done but mounting a couple radio switches and one battery pack.
Matt

Mudsurfer1234

Turned out it didn't stop raining, so no maiden today, we will try again this tuesday evening.

morecashthansense

Hi all,

I feel a lot better now, I have double checked the cog and measured at 6 7/8!! which works out just at the rear of the yellow trim line. This is with a 4400 relion on the firewall and a set of 4 '1950 fa-up nimhs' on there as well. My smoke pump will go on the side of the engine box (200g) and the receiver battery may go back on top of the wing tube. so if this plane can fly well at a more rearward cog such as 7"+ I can move the receiver battery back further...

On another note I can easily fit a smoke tank next to the main fuel tank if I were to fit them sideways.........

I can use a 14oz for the gas and the original 20oz for the smoke they don't protrude above the canopy line and make quite an elegant solution.

Question is if the pipes were run accordingly in the tanks can anyone forsee problems fitting the tanks this way re engine running, also how long a flight are you getting from the 14oz tanks?

flat spin

Not sure, I had this conversation today and I reckon you are looking at 35 mins on the 24 OZ tank which is 0.69 oz a minute so 14 oz 20 mins. I have a spare 16oz which i think i am going to use. Ayt the moment i have two flights per tanks but you do notice the difference on the second flight.

Heritage rider

My Feedback: (2)

For you who have both the 87" and 68" EF Yak.

I have followed and read the entire 87" thread and a lot of the 68" thread. I assume it would take about $1k to do a proper 68" and a bit more than $2k for the 87". Both sound like superb performing airplanes. Assuming that I would equip them as recommended by Chris EF, I am trying to understand the advantage of the 87 over the 68. I am currently flying a UCD 60 and a Funtana 40 with Saito's 100 and 82 respectively. I read a lot and fly as much as possible which is not as much as I want. I can do most FAI maneuvers and some 3D, none particularly well but work at it when I fly and try new stuff all the time. I do not really have sights set on competition but would not rule it out, even though I am older than most newbies in this hobby. I flew a bit 35 years ago or so and re-entered a year ago.

Here is what I think the aswer is. The 87 would be more stable and handle more wind than the 68 and therefore give me more days to fly (we have a lot of wind near the coast in Palm Coast Fl just south of St Augustine). It also would be less expensive to operate from a fuel vs. gas point of view. Plus, bigger is just more fun. Assuming I can afford either, is it worth the extra $ for the 87"??? Why?? My best to Maudib.

Jim

Hammbone

My Feedback: (309)

Like they all say bigger is better. Bigger flies better.
When I first started out in this hobby, I always heard people say that, and I thought "yeah, I'm sure they fly a little better".
Once you fly bigger planes though, you are amazed at how much better they do fly. There is a big difference in how much better bigger planes fly.
That being said, you just have to decide if you want to spend that much more money for a plane that will definitely fly a lot better.

Jim

wgeffon

My Feedback: (4)

Hi Sal,

I'm not totally sure I understand your question but here goes.

If your using 140-150 atv you have all the resolution available at that time.
On your low rates your just using less throw but still have all the resolution there.

On my Yak, (without going to look) I think my low rates are more than the numbers you stated with expo around 35 to 40%


Does that help or did I mess that answer up?
It wouldnt be the first time..

flyingcrazy

My Feedback: (28)

Got my DA50 I just dyed the standoffs the Yak is on the work bench maby it want take long to finish .

r180reef

My Feedback: (7)

Rodney, Flip your carb 180* before you mount the engine. Cut a piece of Tygon long enough to reach from the spacer nipple (on the bottom) to the diaphram nipple (on the top). Doing this will line up the throttle linkage. Have fun with it. Ron

flyingcrazy

My Feedback: (28)

Thanks Ron I saw that a page or two back . You would think that DA would not have changed it 180 deg. unless their was a reason . Unless they were trying to save money on the tygon . They must not be making much money ! lol

flat spin

I have been flying the 87 now for lets say two gallons and yes bigger is better there is no doubt. The plane just keeps getting better all of the time. I did however after some time go out and fly my 68 and had forgotten just how much i love that plane. Either plane will blow your past experience out of the water and each will teach you to fly better more quickly than what you have at the moment. The question is what you are comfortable with and what can your pocket take in one go.

Each one will put a big smile on your face for a long time so it really is whatever suites you the most.


By the way on the carb side of things. A freind of mine did flip the carb over, carb only and ran it on a bench. Out of interest he gave the bench a good kick and sure enough it died. This happened every time. He flipped it back over and the problem was gone. I left mine the way i found it with the mod and have not had any trouble although i know you are supposed to be able to flip it as long as you leave the reid block in place but this guy is well versed in the way of the engine

Dave763

My Feedback: (1)

flat spin, did you have to modify the firewall or servo mount, to use the engine without flipping the carb over?

flat spin

Yes, I spent a long time deliberating over what to do and in the end had to make a hole in the firewall. Not the end of the world but it meant i had to run a piece of tubing over the sleeve of the throttle linkage so that it ran smoothly tyhroughout the transition. I had intended to run my throttle servos outside of the engine bay anyway and ended up putting it on the left from rear next to the tank. I just cut a bit of the polystyrene away and made a little platform for the servo to sit in.

TailTouch

My Feedback: (54)

PHEW !!!
I was getting worried last night coz my CG was about 1/4" to 1/2" behing the TE of the yellow stripe. I guess I am fine. Will have to fly it and see...

Another question ?

Does the flimsy little lid on the engine box add any structural strength to the motor box by epoxing or not.
I'd like to make it removable coz my throttle servo and regulator is inside the box.

Cheers.

ckoerner

My Feedback: (2)

Matt,
Glue the top piece on. It will not be a problem to access it. Just cut a hole in the covering.

flat spin

I may be completely wrong here but i don't think so. Put it this way i don't think it wil be the difference between an all out structural faliure or not. If did mine again i would make it removable. Having said that it is easy to just cut the covering and put a square patch over it althouhg if you love love your yak as much as me it is almost like taking a scalpel to your own skin.

JWilliams

My Feedback: (6)

Yes, it does add some structural integrity. Do not leave it off, glue as it says in the instructions. Well, we got some good weather around Louisville today, so the 87" yak will maiden. Results later today.
Jeff Williams

Dave763

My Feedback: (1)

Is anyone who flipped their carb over had any problems with the engine quitting when bumped?
Maybe DA changed it for a reason.
The post by flatspin has really got me thinking. "this happened every time, he flipped it back over and the problem was gone"