av8ersteve

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Hey all. I have an old but very well maintained RAM 750 that runs great. Only 2 hours on it since last serviced. I'm going to put it in this Eurofighter and was wondering if anyone has had any experience with this jet. I have always wanted a Euro. Is this a good one? Is there a better one out there for around the same price? Thanks.

http://www.grumania.com/xtcommerce/J...hoon::238.html

dandavies

i have just purchased one without a turbine .. looking forward to sorting it out.

HarryC

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Dan, that's actually a different model. Steve no doubt means the 1/8th high-scale model that is on Grumania's website. What you have got is the 1/10th semi-scale model which Grumania no longer makes. I used to have one with a Wren 70N engine and it was great fun. Yours has been modified to have a rudder, the original kit didn't have one. Mine had quite a large dutch roll wobble in some stages of flight but an aileron gyro took care of that. I wouldn't go less than 70N, and an 80N engine would be a blast.

Steve, my experience with the smaller Grumania Eurofighter, and a Eurosport tells me that they do need a lot of thrust, not just to get the vertical climb off the runway but because the drag rise when you pull hard back on the elevator in a tight turn or a tight loop is astonishing and it is quite easy to bring them to a stop if you don't have enough thrust. I don't know what thrust the RAM 750 has but as a rule of thumb if you have a thrust:weight not too far away from 1:1 then you will also have enough thrust to overcome the drag at high alpha. I haven't had that Euro from Ilja Grum though I have seen it at JetPower show and it looks very good, I had the smaller Euro from Ilja and it was fine. I am not aware of any other available Euro at that scale.

dandavies

yessir absolutly correct 1/10 well spotted sir, harry what is your recommendation in turbine then? i have been recommended to get a kingtech 80 not a bad price for 1400 pounds.
a wren 80n is it chief?
this is my first turbine jet i have years experience flying and im a member at dmac flying club and wont have problems with a waiver to fly ide say my experience is classed as confident flown all sorts over the years mainly low wing taildraggers 30/50cc gassers ,had all sorts of 90mm edf jets and its time.. well,it was time a few years back but its took me ages to actualy get in position i can afford to purchase one .. ile be building the zirolli turbonator soon also , nice idea the gyro on ailerons i probably will have one fitted as well cheers.dan

HarryC

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It's not an engine I have any experience of, I expect it will be ok, what you need to check is its weight compared to the Wren 80 which is the size and weight of engine this model was designed around, for example the old Jetcat 80 is a big heavy engine and totally unsuited to this small model, so just because an engine has "80" in its name doesn't guarantee that it suits this model! The model was designed for a 1.5 litre fuel tank which means shorter than average flight times, you would normally aim for 2 litres with a 70-80N engine. Yours might have been modified to take a bigger tank though Ilja Grum advised against it due to the extra weight. If not, just accept the shorter flights and don't ever fly so long that you run out of fuel, deltas glide vertically downwards!
You might find that it tends to nod up and down on the noseleg when taxying, don't worry because when you apply power for takeoff it pushes the nosewheel down into contact with the ground and so you don't lose steering at that vital time. As with your edf experience, the rudder is rather ineffective at low speeds as it doesn't have the propwash over it.
Despite its nose-high sit on the ground it still needs a definite pull back to get it airborne. Generally, deltas are very forgiving and don't stall in the normal way of dropping the nose and a wing tip, you can haul the model around with sticks in the corners and it won't bite back - except that anything involving pulling well back on the elevator such as a turn or loop causes a huge increase in drag so make sure you have plenty of power before you pull back or it will come to a stop pretty damn quick! You can stall a delta easily, but they remain in full control, they don't drop the nose, they just mush down steeper and steeper with a high rate of descent. The fact that it hasn't dropped the nose and still responds to the controls fools you into thinking it hasn't stalled, but it has so when you flare to land it lifts the nose but keeps dropping at an ever higher rate! So beware if you get a high rate of descent and the model is level or nose high, you can still raise the nose but it won't stop the descent, what you need is power and lots of it.

dandavies

thats great information harry thank you , i appreciate your time to explain those few traits to me , top information on the way it handles .thank you ..i will research some more on turbine weights right now and see what the difference is ,maybe a wren 80 would be the way to go. tried and tested is probably best .thanks 'dan

dandavies

wren turbines currently look not to be selling turbines..crap ;(

HarryC

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They are, as wren power systems, their web server got corrupted today and they are waiting for tech people to sort it. However the kingtech will be fine if it is a comparable weight.