zayzay1

the new 88" yak has the same wing area as the ultra rc yak, yet weighs at best 2lbs more, and at worst 4lbs more...?

This is just a question, I do not currently own the ef yak. I am asking everyone who has more experience. i plan to get one a couple of months down the line.

EXTREME FLIGHT

Although advertised as 87 inches and 1450 sq. inches, the Ultra RC Yak is actually 85 inches and about 1380 sq. inches.
Our new Yak is exactly 88 inch span and a true 1450 sq. inches. 17 lbs. will be easily achievable with a DA-50 on stock muffler. The airplane flies extremely light!
But you don't have to take my word for it-the container has arrived in Long Beach and the first 20 customers should have their planes in 10 days or so. We'll let them do the talking.
The new 88 inch Yak is our re-entry into the 50cc gas market-there is NO way I would consider releasing a plane that wasn't at least as good as our previous design-this one is better.

zayzay1

so I understand that it is essentially a larger plane like going from 28 to 31 percent,

but the wing loding on the new yak will be higher from about 26 ounces on the last generation to about 28 ounces on the new one.

and the same engine is expected to pull this extra weight or is a larger engine recommended.

also what size prop can the plane clear.

zayzay1

anyone have anything to add,,

edgeman55

My Feedback: (25)

I am flying the original Extreme Flight Yak at the same size of the Ultra Yak.It is 17lbs 4ozs with a DA50 and KS tuned pipe.It performs liked a scalded ape at 5000ft elevation.The new one should fly great and the videos on Extreme Flights website prove it.Those videos are with a new,not broken in DA50.I had my Yak down at 16lbs but ended up adding another NiMH battery and pipe to increase the wieght as I like the way it performs in the high wind conditions.It is still unlimited vertical and will 3d with the best out there.

Richard D Bahmann aka/Wrongway

My Feedback: (42)

ZayZay1,

I just put my well broken in DA-50 with NX-22-8 prop on a digital fish scale this past weekend. With the standard DA muffler (side dump) I got a solid 29 pounds of thrust. Now I might imagine that would come down one or two pounds in the summer.

So if you went with a stock setup you might see something like 27 lbs thrust on a 17.5 lb takeoff weight that would be 1.55 to one power to weight.

Add a tuned pipe and pick up a pound of weight and 5 lbs thrust (educated guess) and you might see something like 1.73 to one power to weight. That would be ok in my book.

If you are starting from scratch and need ultimate power, watch the EF build thread and see what Chris gets on the Brielli 60.

Bigger airframes do fly better!

shakes268

Is that wet? 17.5 lb with a full fuel tank at take off?

zayzay1

is the one in the 3d video on the extreme flight site with or without the pipe.

Josey Wales

My Feedback: (61)

with pipe

matus777

The ONLY thing remotely negative about the orig EF Yak was that it was too light for precision in strong winds......SO that should make this new one just about PEREFECT.

torqmeister

Zayzay1, are you currently flying a 50cc class Yak. And if so, who is the manufacturer.. In case you have been in hibernation for the last 2 yrs, other than the Ultra RC Yak (which is an exact copy of the original EF Yak), most of the 80 - 85" Yaks out there run in the 17 - 18+ lb range with 1250 -1350 sq in wing area. The exception being the QQ 85" Yak. So where is the problem with a 88" Yak, 1450 sq in at 16 1/2 - 17 lbs? If in fact you have been in hibernation, now you have some real world information. If not, then you soun a whole lot like a TROLL.

torqmeister

Zayzay1, have you seen the first video Chris did on the new Yak? If so, did it look like it flew " heavy " to you? Wake up & smell the coffee.

I have an original EF Yak that started at 15 lb 2 oz. After 5 major repairs it is at 15 lb 8 oz, with 140 flights on it, it is an exceptional aerobatic & 3D aircraft.

With that kind of experience, don't you think I would be looking forward to Chris's new offering. Of course I would. Put that info together with all the great planes he has brought to market, do you think he would bring a "dog" this time?

zayzay1

I am just trying to get information from everyone else since I really have very little experience with gas planes especially over 77". I just see it this way I could get the original ef yak 87" from ultra-rc or I could get the new 88" yak and I would have to stick with it for a while, because either airframes comes out to over $700 shipped. I just want to make the right decision no troll here,,,

and what I have gotten from all of this is that the 88" is a bigger plane and of course bigger planes fly better.


ohh and videos from any company always leave a lot to be desired,, usually knowing the exact setup is a plus, and so is the lbs of torque that the engine was putting out.


(and yeah it so far seems alot better than all of the competition) almost everyone else is 17lbs and over with a smaller airframe

rcblimppro

There are so many behind the scenes details that in the end make of break an airplane design. You simply can't go by size and weight only. Airfoil selection and thickness, position of wing and stab with relationship to thrust line, canopy shape and a great many more little details will in the end determine how well the airplane will fly. The Radiowave 40% Extra is a fine example of this. It is bigger, heavier that most offerings in the 150cc market. Did that make it a pig of an airplane? Absolutly not, the airplane through design carried the additional weight very well. The airplane has the ability to track well at lower airspeeds and not feel underpowered. it has and continues to do well in the IMAC arena and placed well in the 2002 TOC at high altitude. I would expect the same is going to hold true with this Yak. I myself will never understand how an airplane that has yet to be delivered to customers can be faulted. I look forward to seeing how this new Yak is going to perform. I still have hopes that Chris will put out a 40% Extra 300.


Shawn

MustangAce

My Feedback: (3)

I really want to know what the CG is of the airplane in the video?????

torqmeister

I would guess it is neutrally balanced. If my info is correct, it was one flight, broken into 3 seperate videos, IMAC, hovering, & 3D. The plane seemed to do all of them well. It did not appear to be nose heavy, making it difficult to hover & 3D. It also did not appear to be tail heavy. It didn't appear to be sensitive in pitch. I'm sure there will be a range of CG recommended in the manual, and a real world concensus from the guys who build this Yak.

Maudib

My Feedback: (51)

Best thing to do is just wait... planes are on US soil as we speak and will soon be in the hands of twenty very anxious new expectee's...

I'm one of them.

We'll know weights, loadouts, opportunities for lightening, etc...

From just switching to stock muffler will save nearly 3/4 lb... CF gear might save 6 OZ... Leaving spats, gear fairings and fake louvers off... another 5 oz

Chris stated his airframe weighs 10.38 lbs out of box...

I add 6.5 lbs with a stock DA50/muffler setup coming to 16.88 lbs...

If I leave of the spats, fake louver and gear fairings (purely choice options, scale acoutrements) I'm at a little over 16.6 lbs

And if I wanted to maybe save the 6 oz with CF gear? WELL under 16.3 lbs

Now it's possible Chris missed a part or something in the weighinging... we'll find out soon enough... I doubt it though...

As I said.... we'll all know soon enough from firsthand experience and actual loadouts...

torqmeister

Zayzay1, there is a lot of talk on the other thread about cannisters, tuned pipes, 60cc engines, etc. You are a little closer to sea level than I am,here in Texas, so a simple, light setup with a quality 50cc engine & standard exhaust will provide superior performance from this plane. It would be much more affordabe,too.

I don't think specific torque figures are important. They differ with geography,air temp, humidity,engine, props, fuel mixture,& probably other factors I haven't thought of.

Rush7

My Feedback: (74)

I agree with Maudib. The planes are here in the US and soon to be in the hands of twenty lucky people. Lets just sit back get a bag of popcorn and see what kind of setups these guys use. Then we will have all the real world answers to what kind of plane this is going to be.

Tor

I don't think it looks too heavy at all on the videos as far as wingloading is concerned. As rcblimppro correctly wrote, wingloading is by far the only parameter. And according to one of the other threads, it's even 18.5 lbs dry, so probably 19 lbs wet.

However, I think it* lacks power in the videos (my oppinion - feel free to disagree). Considering how light it seems to fly, it looks like it could handle an extra few pounds for an 80cc and would benefit from it to overcome the increased drag, which is probably more of a concern than the weight.

* "It" being the specific combination of model and engine as depicted in the videos and discussed in this thread.
[Edited for clarity for Doug, post 23]

flat spin

Forgive my ignorance but since when has drag been a problem. Most people talk about how nicely a plane slows up on down lines or how easy it is to keep a consistant speed. Drag won't imact on immediate pull out either, you may not accelerate so fast but the power to hold the model and get out of trouble will still be there, no?

EXTREME FLIGHT

Tor, in what maneuvers do you feel it lacked power?

Yak Man

My Feedback: (1)

I thought Extreme Flight just built the plane, I didn't realize that Extreme was responsible for the lack of power or the motor we put on the thing?
Maybe I should read the fine print under : Motor 50cc to 60cc

Good Day!

Maudib

My Feedback: (51)

YakMan... Now now....

You CAN easily fo this plane with the stock muffler and be real happy... especially if you do the few little things to keep it light as possible.

Flatspin you are SO right... in 3D/high alpha maneuvers... drag isn't a concern... and that "drag" also adds to the lift coefficient in all attitudes.


Tor... we've already been down this road... you prefer more power than what you feel is evident in the video... that's perfectly fine... but that is subjective.

I thought it was quite decent... and based ont eh airframe weights, I don't think CHris' 18.5 lb weight is going to be the norm with a DA50... sub 17 lbs is doable and that's without seeing the airframe.

I'm shooting for 17.5 lbs with the Brillelli 60... and will love every minute of it...

Tangy Tom

Forgive my ignorance but since when has drag been a problem I assume he is talking about for IMAC where drag, power and weight all play an important part on how the model will perform.

To my eyes it looked fine in the pull out. Not amazing by any means but pretty good. Think it would struggle a bit in a one roll rolling loop though.

T

ps just a thought, this model is for 50cc right, coming in at ~17lbs. 50cc for 17lbs equates to 51lbs for 150cc which I would say is heavy. Most 150cc models are late 30's early 40lb range. Basically I'm saying that, IMO this model is not 50cc size, at least if you're wanting excellent IMAC performance in ALL weather.