SAP_2000

Went down to the field today to try out my Merlin 160 for the first time and possibly do the maiden on the just finished Eurosport II.
The Eurosport is built pretty basic to save some wheight. Just added inlets and by-pass for FOD protection and the Kevlar fuel cells. No speed brake, gear doors and one servo in each wing etc.

The Merlin started very smooth and stabilized @ 32K rpm. I did some taxiing and sub-trimed the nose wheel and did some brake tests. I used up a full tank of fuel checking that the tanks drained in the proper sequence while just playing with the engine reving it up and down, shut downs and start ups etc. Temps was about 560 deg at idle, and about 640-660 at full rpm, peaking at 700 deg during the acceleration.. The throttle response is by far the best I have seen yet. Pretty normal acceleration up to ~60K rpm, and then just a ''bang'' up to max rpm. My best guess is less than a second.....

All things OK, then it was time for the maiden.
Went to full throttle and the acceleration almost scared me... I actually eased up the throttle a bit....[X(] Take off was in about 60 meters. A few clicks of trim here and there and it was flying on its own. Did a few laps around the field to relax my self and then brought in low over the runway at low speed. Flew past me 5 meters over the runway with about 30 deg AOA @40% throttle and then slammed the throttle as it pulled in to vertical. The ES not only managed to climb from slow into vertical, it actually accelerated with authority towards the sky.... I did about 10 more of those high alpha to verticals and noticed that every time I slammed the throttle at low airspeeds, the plane dropped the right wing a bit like it was torquing....? This happened every time I tried it. Could it be that the very quick engine acceleration makes the plane torque slightly..??
Then the 8 minutes on the timer was gone and it was time to land.

Stupid me forgot to bring a full can of fuel, so there was no fuel left for more flights.... Did not matter to much as it was pretty cold (-3c), and I was the only soul there today, so I just packed up and went home..

What a nice day...[sm=sunsmiley.gif]

Sorry, no in-flight pics as I did not dare taking pictures while flying...

Dave03B

well done. Sounds like you had and will have a lot more fun with it.

SJN

Congratulations Stsale. Glad you got another Eurosport

Sounds strange that it drops a wing a bit......

Are you using the stock exhaust pipe ?
Have you messured the thrust with the engine in the plane ?

SAP_2000

Hi, and thanks Sonnich!

I never managed to forget how well the ES flies. Even though I only got about 10 flights on my first ES before it was intentionally shot down (jammed), I immediately recognized the ''ES'' feeling when I got it airborne today. I know I will love it long time...[8D]

Yes I think it is strange too. I have never experienced that before, but I also never had a engine that accelerated so quick before either.... Don't know how much the rotating parts of the engine weigh, but say it weighs 1/2 kilo, and that half of kilo accelerates 60.000 rpm in less than one second, it must produce some sort of torque....? I can't really think of any other logical reason.

I am using the stock pipe with the bell-mouth mounted to the by-pass. Distance between the nozzle and pipe is 2 cm. I am not sure, but the pipe may be slightly bigger than the one I had on my previous ES.. Anyway, it REALLY accelerated from slow high AOA to the vertical with almost full fuel tanks (4.4 liters), so the pipe can't be decreasing the thrust much... It was cold today. About -3c, so that probably gave a bit more push too...

KFalcon

My Feedback: (18)

Congrats!!

What happened to the first one? Shot down?

LN-JET

Torque;
If I remember my lessons in gyroscopical forces, and your engine runs the same way
as the others, a pitching up moment would make it yaw to the left.
This does not correspond to a dropping right wing.
You should not get any torqueing action around the shaft (roll) axis of the plane.
I might be bull****ting , so please correct me anyone..

Lars

SAP_2000

He, he. Long story...[] And yes it was purposely ''shot'' down....

See this thread:
http://www.rcuniverse.com/forum/fb.asp?m=1134680

and then read this one:
http://www.rcuniverse.com/forum/fb.asp?m=2093885

icepilot

Congratulations, Staale!!

You should have called me - I would have been there with both my camera and my F16!!
You know I'm longing to fly again even though I'm a married man now!!

Glad the ES flies so well, and the new turbine sound great!

Anyway, give me a call next time - I would love to see that Merlin in action!!

Tor

SAP_2000

Now you got doubting my self....[&:] I am 95% sure it was the right wing that dropped. The engine is rotating counter clock-vise when seen from behind...
I don't think it had anything to do with pitching as it also happened at slow high AOA flight when I slammed the throttle without going vertically.... I am no expert, but I was thinking that it was the weight of the rotating parts in the engine that was causing it when it accelerates from 60 to 116K rpm. in less than a second... But again.. I am just guessing...

Anyone who got a theory and could bring some light to this??

SAP_2000

Sorry Tor. But I so suddenly decided to by my self....(shaming)

But I thought that now that you are married, you only stay at home baking small coockies and rubbing the new wifes feet....

I promise to call you next time...

icepilot

You've got it all wrong, Staale - when you're newly wed you rub other parts of the body....[>:]
The feet rubbing happens when you've been married for 5-7 years!!

So - lets go flying soooon!!

Anyway, if your turbine rotates counter-clockwise and you revv it up very fast, you will have a clockwise
rotation as a reaction... giving the right wing drop that you descibe..

icepilot

But then you said from behind - meaning that you peeked in through the tail pipe?? Then it should torque to the left..

KFalcon

My Feedback: (18)

I remember the whole situation now. I have slept since then...

Stig Andersen

HI Staale.

I had the same thing on my ES with the SimJet Nexus turbine. It is the gyro effect of the turbine that forces the model to roll slightly. At first I started checking the throws on the ailerons, but they were OK. The I checked the incidence on the wings compared to each other Everything was OK. Then I spoke to one of my modelling friends here in DK (Motor Carl), who is an aeronautical engineer. He told me about the gyro effect. On engines like the Merlin and the Nexus, the rotating parts are quite heavy. That, compared to the relatively slow speed/low wingloading of the ES, makes the plane drop a wing.

Just my 2 cents

swissflyer

First: my congratulations for the Eurosport... is a fantastic bird...


second: shall we now add a new mix on the radio?? when givin full trottle on the turbine, the ailerons should move a little?? [>:]to compensate the torque??...or install a gyro like on the Helis???[:'(]

it sound interesting, where are we going now with this powerful turbines...???

Alexdu

My Feedback: (3)

Staale, congratulations on the maiden. Finally some experiences with the new Euro. I just received mine last week and will start construction this week. Upgraded P-160 will go in mine, or should I called it a Titan now........jejejeje

I have several question if you don't mind:

1- The wing now comes reinforced for the the landing gear. Did you leave it as is or did you reinforce it some more?
2- Front gear mounting is installed. Again did you leave it as is?
3- Canard setup stock or modified?
4- Overall how did construction go on the Euro II compared to the old version?
5- Did you perform any modifications/improvements?

Regards

Alex

SAP_2000

Thanks a lot Alex. Yeah.. 160, Titan or whatever... Not easy to know... The web sites here in Europe says nothing about ''Titan'', Just P-160 the last time I checked. My guess it that the MK III is named Titan in the US because of the previous problems with the P-160.

Of course not. Glad to help!

I left it as it was. Looks much stronger now than it did on my first one. My first one was a early one, and I think the beefed up gear mounts came later on the MK I.

Left it stock. Seems very strong to me

Stock, but I used the canard arms that I made for the first one. Todd @ Dreamworks RC sell machined aluminum canard arms.

A friend of mine helped me out quite a bit due to lack of time lately, but it goes together much quicker than the first one did. Compared to the MK I, you will save a lot of time on the vertical fin, nose gear mounting plate and the cockpit in addition to the fact than it now can be built pretty stock. It was a bit difficult to get the canopy in to the fiberglass frame. I had to split the bar that goes over the pilots head in two to get it in there.

Not really, except for the canard arms.
I Will probably secure the big main hatch with a second set of mounting plates and screws at the middle to prevent it from ever coming off in flight.
I would recommend getting the inlets and the new Kevlar tanks. The tanks come with its own pre-cut formers that secures them in the fuse and makes for easy removal/ installation. I also put in a 20 oz Du-Bro tank between the main tanks under the inlet as a header tank.

Alexdu

My Feedback: (3)

Staale

Sounds good. Yes my first impression was that it would be a faster build, which you confirmed. I have the grey scheme and will add speedbrake and gear doors. At this point I will be going for a scale look. Some friends of mine really like a scale scheme, that to my knowledge no one has done yet. I'm still not convinced, but they have some time to convince me..........jejejejejeje Otherwise I will go with a sport scheme.

Regards

Alex

SAP_2000

Thanks!


Yeah. Maybe we should start to install head-lock gyros on our jets to...
It just gently drops the wing about 10-20 cm, and only at low speeds. Nothing dramatic like a tip stall etc. Only a slight aileron correction is needed to level it again.

lov2flyrc

My Feedback: (24)

Congrats Staale!!

I dont experience the wing drop on mine with the Merlin installed?? I know Gaspar has quite a bit of time on his Euro/Merlin combo, perhaps he'll let us know if he experienced any wing drop on his.....

Lets se some video
BRG
Todd

SAP_2000

Yeah, Todd.
It was the strangest thing.

In a post above, Stig said he had also noticed it on his ES with the SimJet Nexus. Just last week, I witnessed a bench run of the new Nexus with Gaspar ECU, and it has the same great acceleration from 60-70 K rpm and up as the Merlin.
It only happened when the airspeed was really low like flying at 30-40% throttle with high AOA. It happens at the very same second as the engine just ''bangs'' up to full throttle.

Give it a try the next time you go out and fly your Euro....

Theoretically it is not that strange. Try and hold a powerful 500 sized electric motor in your hand and feel the torque in your hand when you give full power at once. It will almost twist itself out of your hand. Then try to use 3 or 4 seconds on the acceleration, and you almost won't feel any torquing at all.... And this is on a small electric motor where the rotating parts weigh maybe 30-40 grams.

SAP_2000

Great to hear that I am not the only one..

I was almost starting to believe that I had imagined the whole thing in my head.....[sm=bananahead.gif]

lov2flyrc

My Feedback: (24)

Staale,
Not saying it is not possible, just hadnt seen it. I may come in on power a bit slower than you are too?? I see if I can get it to do it next time i'm out... Congrats on the maiden!
Todd

Delta Mike

My Feedback: (18)

Hi Staale, Do you have any other photos of your new EuroSport? Maybe diferent angles, I am considering purchasing one soon, Just like to get some good shots of it. The photo's you have on that last post are great but they crop out the wing tips. Email me if you can.

Warm Regards,
Dennis

[email protected]

SAP_2000

Sorry Dennis, but those were the only ones that i took yesterday, except for maybe two more.

I would gladly send them to you in better quality if you like...? Just tell me the size you want them in....