Over a period, especially when learning to fly, you find you need to change
the rotor blades on your Twister CP V2 Helicopter. This article describes the process of
removing the current ones and installing the new ones.
Clear work environment of at least 80cm wide by 60cm deep.
1.5mm Alan Key
Step 1 – Removal of blades.
Using the Alan Key, unscrew the screw (036) holding the Main Blade (042) to the Main Blade Clamp (037) ensuring you keep your finger over the nut (xxx) on the underside of the Main Blade (042) to prevent it dropping out and getting lost. Once you have unscrewed the screw (036), remove it and carefully slide the Main Blade (042) out of the Main Blade Clamp (037). With the Main Blade (042) out, you can concentrate on getting the nut (xxx) and storing it safely.
Make sure you don’t loose the nut under the bracket – click to see largerUnscrew the screw ensuring you don’t loose the nut on the bottom of the blade clamp. (click on image for full size)
Repeat this for the other blade if required
Step 2 – Inspect
Check the new Main Blades (042) don’t have cracks or scratches especially on the leading edge and around the mounting area.
Check the Main Blade Clamp (037) to make sure it moves freely and does not show any signs of cracking or un-due wear and tear.
(Remember: The blades on you Twister CP V2 Helicopter have considerable stresses applied to them and they have the potential of doing considerable harm and damage.)
Step 3 – Install new blades
Fit the Main Blade (042) with the leading edge of the blade on the clockwise side when looking from the top into the Main Blade Clamp (042) lining up the hole for the screw (036).
Install new blade with leading edge lead when rotating clockwise
Insert the screw (036) into the hole and using the Alan key give it a half turn to get the thread bitting. Then insert the nut (xxx) into the cavity on the bottom of the Main Blade Clamp (037). Now continue to tighten the screw (036) with the Alan Key until firm.
Use the screw and nut removed in step 1 to secure the Main Blade to the Main Blade Clamp. (click on image for full size)
Line the Main Blades (042) up straight and at right angles to the Fly Bar (003). Tighten the screws (037) and nuts (xxx) firmly so the Main Blades (042) will just move.
With the first flight following fitting, bring the throttle up slowly monitoring the blades.
The following is the assembly schematic out of the Twister CP V2 Bell/Hiller Carbon Rotor version. Click on the thumbnail to see full size.
Twister CP V2 Helicopter assembly schematic (click image to see full size)
With either a JetCat or a Wren turbine which operate on Jet A1 fuel exactly the same as the real jet turbine engines found in that Qantas jet that lands at Adelaide airport, these model aircraft are an incredible piece of engineering. When you hear them before seeing them, you’ll swear your hearing a real jet engine.
Jet turbine driven model helicopters
How fast?
I don’t really know yet. The US FAA has placed a speed limit on these models of 377kmh (234mph) however these pilots report faster speeds than that. To put a little perspective around this, a Cessna 174 (typical single engine 4 seater) has a top speed of 320kph (200mph) at sea level.
The helicopters seem to get speeds up to about 140km/h, a little slower than their real life counterparts but not much.
Fuel
These engines use the same fuel as their the full size versions, Jet A1, 1-K kerosene. So when you are around these planes, you’d swear your at the airport. Fuel consumption varies but as an example, the JetCat P160 uses 454 grams (16 oz) per min at full power.
How the engine works
They really work the same as the full size engines with the main difference being the size of the parts used. They have a compressor, combustion chamber, turbine and exhaust nozzle. Air enters the engine and is compressed by the compressor. The compressed air is moved through the combustion chamber where the air is heated, making it expand (and compress even more). This air moves through the turbines at very high speed which makes them spin. A shaft is connected to the turbines and back through the front of the engine which connects to the compressor blades turning them. The air from the turbine stage exits the engine through the exhaust nozzle at very high speed (about 2,000km/h or 1,300mph) which pushes the engine and plane through the air.
With the helicopter, there is a second shaft connected to the turbines which goes through a gearbox to drive the helicopters rotor. In this version the air coming out of the turbines is exhausted and not used for thrust.
Two good articles that explain this with illustrations is:
JetCat P160 Jet Turbine engineHelicopter powerplant using a JetCat Turbine engine.Alternative helicopter power plant using a JetCat Turbine engine
How much?
If your anything like me, I have to know what would a hobby like this cost me? Well here’s what I found out so far. Please note, I don’t sell these and the prices here are what I found the things for on the Internet at the time of writing.
Engines:
Prices range from AU$3,400 for a JetCat P80 to AU$7,600 for the JetCat P200. For helicopters, you would spend about AU$7,300 for a SPH5 Helicopter Power Unit.
Plane:
I’ve found kits start at about AU$1,200 for a Boomerang Intro ARF Jet Kit and work up from there. The sky really is the limit as some of the planes are really impressive with enormous amounts of time going into their construction.
Controllers, computers etc:
You need to be able to control these models and they don’t come with a controller. Most hobbyists have a tendency to like a particular controller so its left up to the individual. Priced that I found started from about AU$199 for a simple 4 channel radio kit to AU$3,350 for a Futaba 14CH Radio Control System.
So for a full kit, one should expect to start at about AU$6,000 when you get the other bits that are not included, with most hobbyists spending much more.
A tip:
If you don’t have experience in flying these models, start small and cheap. When they crash, there is usually nothing left.
The next two pictures are of a B52 Remote Control model aircraft which was flown by someone with experience. You can see the results anyway.
Remote control B-52 aircraft before takeoffRemote control B-52 aircraft crash site
Comment from a YouTube viewer explains a little what happened:
pete2778 (6 March 2007) I was there and saw this happen, RAF Barkston Heath, Lincolnshire, England, August Bank Holiday Weekend in 2005. It was the BMFA national championships. It was blustery but many other models were being succesfully flown. The problem was that the roll spoilers on the B52 become very ineffective past a certain angle of roll, a gust pushed it beyond that angle and the rest was history. Sure looked realistic, most realistic model crash I’ve ever seen!
Where can you buy (in Australia)?
This is not exhaustive, it’s what I found in a short time of looking. If your a dealer, and want to be listed here, feel free to drop me an emailÂ
Trev’s suggestions on the best way to manage your domain name
Domain names are a vital part of your hosting and mail system and is often forgotten as it’s the part that sits in the background quietly working until one day it does not. This is meant as a plain english guide to help would be web masters understand how to set up the management of their domain name to reduce the impact of outages on the internet.
First, what is DNS
DNS stands for Domain Name Service.
Human’s like to use names. A name has a meaning. The internet can’t use names, it needs numbers. So we have an issue.
DNS is the translator between the human name and the internet number. So my web site here is called “trev.id.au”. That’s what you type in your browser to get here. Your web browser asks the DNS for trev.id.au internet number address. The DNS returns the number (in this case 61.14.187.198). The browser now can ask the networking system of your computer to go fetch the page for the address that the Internet can work with.
Email works in a similar manner. You address an email to user@domain.com.au. The email program first asks the DNS where it should send mail for domain.com.au and what is the number address or IP address. It then tries the address and if it works, it sends the mail.
The key problem with incorrectly managed domains.
The real problem is around email. If an email server cannot resolve your domain name because the DNS is down, it will return the email to the sender with an error that makes it look like you don’t exist. If it’s just a hobby system, not so bad, but if it’s your business, it can be severely damaging.
What needs to happen
You should have at least two physical servers in different parts of the internet doing the resolution of your domain name (the translating between name and number and the telling where to send mail). It’s also a good idea for these servers to be different from your domain name registrar and your hosting provider. I have used both http://www.zoneedit.com and http://www.dyndns.org.
So with two seperate servers capable of answering DNS queries for your domain and email, and these in two different physical locations, both have to be down for your domain to be down. Chances, well I’ve been hosting this way for about 7 years now. My site goes down because my server does, but my domain has never and mail always works.
You can host the domain name at zoneedit for free on 2 servers (as per their site at time of writing this)
Email when your server is down
Servers go down. That’s life. What happens to email if your server is down? If the domain name resolves, the sending mail server will generally hold and keep trying for a short while. This overcomes the occasional network outages. For longer periods, the sending mail server bounces the mail back to the sender.
This can be overcome by using a mail forwarder which is a server on the internet that is defined as being the second server if the primary server is not available. It holds a lower priority than your main mail server. This allows your server to go down with no impact to mail from the outside world.
I use this service and have been happy to pay the small amount it costs me each year.
2. Register with a DNS hosting organisation like www.zoneedit.com or www.dyndns.org and set up your domain name. Note this is not registering the name, but it’s getting it ready. You will be given some info from the DNS hosting company in the form of a name and ip address for each of the two servers that are going to host your domain name.
3. With the server information, go back to the registrar and manage your account/domain. Find where to enter the domain name server information and change it to the names and ip addresses provided in step 2.
4. Now sign up with a hosting company. The hosting company will give you an IP address to use for your domain name. You should use the manage interface of the DNS hosting organisation to configure the name and number for domain.com, www.domain.com and optionally, but usually good, mail.domain.com. These 3 names should all point to the IP address provided by the web hosting company in step 3.
Detailed configuration example
[This is under construction]
There are many providers of these services. I’m going to provide the detail around setting this up using www.enetica.com.au as the Domain Name registrar, www.zoneedit.com as the DNS hosting organisation and www.mdwebhosting.com.au as the web and mail hosting company.
