john agnew

I have been flying my new Jetco (see thread) with the excellent Wren 44. The model weighs just over 12lbs dry and, although the Wren flies it very smoothly I felt it could do with more thrust especially in a "go around " situation when the 44 lacks a wee bit of thrust.

I had a Ram 500 autostart in semi-retirement although it had only a few hours runtime. I had stopped using it due to the high weight of the airborne package of just over 4 1/2 lbs including battery. As the Ram gives around twelve pounds of thrust I felt it was not very smart to gain 4lbs of thrust for a weight gain of 3lbs over the 44.

As the Ram is an earlier Wren design I decided to try and convert it to manual start with a FADEC ECU using the one from my Wren54 Mk3.

I knew the hall sensor was not compatible so I obtained a new one from Wren, removed the front cowling on the Ram and substituted the new sensor. At the same time I removed the starter bullet.

The total weight of the airborne package is now 2lbs 12oz a saving of almost 2lbs and a much tidier installation in the airframe.

When the change over was complete I set up the Ram on the test bed, connected everything up and initiated a start. The sequence is identical to the method used to start my Wrens and the gas lit up immediately followed by a very quick fuel ramp and the Ram was idling at 45k rpm and 438o C within 15 seconds. Max rpms are 155k which may be improved on by pump adjustment.

Needless to say I am delightet to have brought my first turbine back into use and will test fly the Jetco as soon as possible.

The cost of the conversion was around £90 which included another FADEC ECU and the hall sensor, well worth it considering the weight saving.

rcguy!

My Feedback: (69)

John,
Nicely done!

Dave Rigotti

john agnew

Dave

How's it hangin'? Saw you had some nice spring weather earlier in the week!! Are you getting any turbine stick time?

John

pecojets

i understand that also you can use the fadec full autostart with ram 500 and save some weight
and add lot of reavility

alfred

john agnew

Alfred

I'm sure you could but it will be reliable with the Eco ECU and you won't save anything like 2lbs with retaining the autostart. The autostart ECU is also quite a bit more expensive than the Eco version.

The weight saving was the main object of the exercise.

John

rcguy!

My Feedback: (69)

John,
Have @15 flights on the Reaction 54. Buddy Russ has about the same on his Intro. My Intro on hold until I get tired of the R54. Last weekend 18" of snow! MOST of it gone today. MAYBE get to burn some kero this Sunday.
REALLY thinking about the YA Starfire 2.

Interesting what you did for the RAM 500. Got to be alot of these out there for a fair price?

Dave Rigotti

john agnew

Dave

If you can buy a Ram 500 at a good price this conversion turns it into a reliable, light turbine. Iv'e put two more runs on it and it is going very sweetly with first time starts, something that the autostart original did not often do!

A couple of the guys have already sent me PM's asking for further details of the conversion, If anyone else wishes I will post full details.

John

L Turner

My Feedback: (3)

I would be very interested in the details for converting the RAM500 to a manual start version with a FADEC. I presume you dispense with the solonids, starter motor & bendix and use an external wand starter motor, battery & switch and some type of external glow plug driver. The RAM ECU battery alone is 9 oz. Which specific FADEC do you use (I have an MW44) and what parameters seem to work well.

The excess weight of the autostart RAM500 is a major problem for my JHH Cougar, about 15.5 lbs wet.

john agnew

L Turner

I have had a couple of requests today for full details of the conversion so I will post them later this evening when I have a little more time.

John

rcguy!

My Feedback: (69)

You da man!

Thanks!

Dave

Mach1

My Feedback: (5)

I would like to do this conversion also but would like to use "air start" via scuba tank for start-up. I think normal air start engines have the air
directed to the turbine wheel and not the compressor. Any ideas on how to accomplish this on the 500?

W.G. Hunter

john agnew

Guys

As I said earlier here are the full instructions for conversion of the Ram 500 to a manual start turbine. It may be possible to use other Eco ECU's I have used a FADEC ECU as supplied with Wren 54 and 44 turbines, the ECU is manufactured by Gaspar Espiell.

You will need an Eco ECU programmed as follows using your GSU or HDT whichever you wish to call it

Max rpm 160k
Min rpm 45k
Stop rpm 28k
Min temp 100oC
Max temp 800oC
Accel. delay 025
Decel. delay 020
Stability delay 050
Pump start Auto +1
Pump start ramp 006

Now set up your transmitter as per the ECU instructions.

You will also need a Hall effect sensor with a three wire lead (The existing Ram version has four wires and is not compatible)

A four cell pump battery Wren recommend a 650mah Kan which is small and light and should be enough for three flights before recharge.
You can, of coursr use a larger capacity battery but the object of the exercise is maximum weight saving.Note that the ECU draws its power from the rx battery.

Thr existing thermocouple and pump can be used.

First remove the front cowl which is secured with four allen screws, then remove the starter unit (three screws) set this aside for re-use.

Then remove the Hall sensor which is attached with two allen screws and two tubular aluminium stand offs. Fit the new Hall sensor. You will only be able to use one of the mountings as the centres are different. I cut down the stand off not being used by 3/16" and let the underside of the sensor rest on the screw head, when the cowl is replaced the sensor will not move.

Fit a 4mm non-return festo coupling on the gas line and an on / off valve on the fuel line between the pump and the turbine. As there is now no fuel or gas solenoid this will prevent flooding the turbine during fuelling. I always open the valve immediately after fuelling, because if you forget to open it, and remember as the turbine is trying to ramp onto fuel and open it you will have a fire due to pressure building up in the line.

You will require a wand starter to spin up the turbine, you can buy one ready made fron Wren of make your own from the existing starter motor, a micro switch and the existing Ram battery. (the photo is the Wren version)

Connect everything up on the test stand fill the tank and open the fuel valve. You will need a 2 volt glow driver to energise the plug and a can of starting gas. Switch on the tx with trim centred,switch on rx and plug in the pump battery. The GSU should now indicate "ready" and show the ambient temp. and rpm's at 00000. Connect the glow driver to the plug, spin over the turbine to about 5000 rpm, remove the starter wand and open the gas valve, as the revs decay the gas should ignite, the GSU will show a rapid temperature rise and as soon as it passes 100oC the display will change to "fuel ramp" you wll see fuel beginning to flow through the fuel line to the turbine. Keep blipping the starter to keep the revs turning over and as soon as you see the temperature quickly begin to rise apply the starter and keep it turning.

You will hear a distinct change in turbine note as the fuel ramps up and as soon as revs hit 25 - 30k the turbine should self sustain, remove the starter and the glow plug, turn off the gas and the turbine should be idling around 45k. This process usually takes about 15 -25 seconds.

The turbine is now under full transmitter control.

If you do not wish to use a starter wand you can retain the starter in place , fit it with a plug and connect this to the existing battery via a micro switch in the lead you just blip / engage the starter as above the battery is disconnected before flight, this method does not , of course save the weight of the starter assembly.

I hope this will assist any of you who are contemplating this conversion. I have probably missed something out! And if you have any queries please post on the thread, this means everyone will get the information instead of me sending several PM's.

John

john agnew

mach1-rcu

Sorry! forgot about the air start! I don't think the 500 was ever configured for air start, but, once you have got used to the starter wand I don't think you will want to lug a scuba tank around. Remember the wand start can be used on any air start turbine.

John

swissflyer

Thanks john!!

john agnew

Alessio

I believe you have ordered the parts to carry out this conversion. Please note that to get the full 160k rpm out of the Ram you will need a five cell battery and not a four cell as previously advised. Although the Wren 54 will give 160k on the four cell I understand the Ram has slightly different fuel injectors and need the extra pump power.

John

swissflyer

Thank you for the information...and yes i ordered the whole to get also my ram500 converted...

i hope this WE i can convert it...

swissflyer

this morning i "converted" mine...it took me about 3 hours, from dismateling the turbine, to the "first firing"...

the manual start is far better than the automatic start of the RAM ecu..
no more flames or 2-3 attemps to start it...
the only think i don't like is the high frequency noise around the idle position (still using ear protection!)

a second RAM00 is reborn..[8D]

Again Thank you John for sharing your experience with us..

john agnew

Alessio

Just got back from holiday today and had a lot of posts to read!

Glad to hear your Ram 500 is running well. It really does improve the reliability for very little cost. What model are you putting it in?

John

swissflyer

hello john,
my ram500 is pushing around a AV8R...

Btw, something strange, the RAM has metric and (no idea how is called) USA ???? standard screws!!

the cowling is old in place by some M3 screws, the starting motors by some USA screws...

a big mix up..[sm=stupid.gif]

and for the hall sensor, in mine i get to fix it using 2 screws...

L Turner

My Feedback: (3)

John,

Any recent changes in the Eco FADEC parameters for your RAM 500 Re-vitalized conversion? I now have a green MW54 Eco FADEC from Wren and am planning to use 4 cell NimH pump & Rx packs (rpm limited to 150 k) to save airborne weight. Will use a Wren Gas valve, thermocouple (connector compatable with the FADEC) and 3-wire Hall sensor. Keeping the bullet starter motor for now, I am planning to use my old six cell 1250 ma SCR pack to spin the starter motor with a Wren switch for manual start.

john agnew

Laura

No changes to the parameters, I have sent you a PM with some info.

John

markdam

My Feedback: (15)

need updates im planning on converting mine any new info????? John have you actually flown this conversion yet?

mat

Im thinking of doing this conversion to my ram 500 just wondering if there is any problems with taking the rpm up from the ram ECU of 150000rpm to 160000 possible with the fadec unit

john agnew

Mat

I have been running my Ram at 160k rpm without problem. I have been using a Wren 54Mk3 tailcone wich bolts on to the existing holes without modification. It seems to give more power and also reduces the full power temp by about 100oC.

John

L Turner

My Feedback: (3)

I now have 5 nice manual (bench) start cycles on my RAM500 Eco conversion, with 5 cellpack for the pump and Vb starting at 6.4 volts. I set max rpm to 150, not to stress my original bearings (now about 250 cycles!), Accel Delay initially 30, now 25; Decel Dly initially 30 now 20, Stab Delay 50 now 40. Pump pack required only 200 ma to recharge after 20+ min running and two cycles. Pump start ramp initially 004 (too slow) now 005. Pump PW about 600 at 150 k with EGT about 620. Might try dropping down to a 700 ma NimH pump pack of 4 cells to maximize flying weight reduction.

Installing in my FACET 1200, I may need to shift the turbine forwards somewhat to compensate for the about 1 lb weight reduction in the nose by converting from the RAM autostart. Alternatively, I have ordered a swept wing from Kerry Sterner, which requires the balance point to shift rearwards about 3/4 ths inch and thus may compensate for the weight loss up front.