：：：：涡喷自制问题解答：：：： 下面基本是英文

1:.发动机如何自己设计？ 到哪里找材料，价钱如何？

Small gas turbines are not scaled down large engines. Any attempt to do so is likely to fail. Kurt Schreckling is to be commended for his original approach to the design of small engines as set out in his book on the FD3 64.He carried out the therorectical considerations and came to the conclusion that a simple radial compressor and turbine wheel with a single annular combustion chamber would produce the best results. His views have been confirmed by the rapid progress in refining the designs and extracting more power from the same basic size. Spreadsheets have been developed by a number of people based on the Formulas in the Schreckling and Kamps books that model the processes that go on in the engine. The GTBA has also commissioned burst analysis of the turbine wheel.
英文来自（GTBA-英国涡轮发动机制作联盟)

模型用的发动机不是大的发动机的按比列缩小，任何试图这样做都很可能是失败。值得推荐的是英国人-Kurt Schreckling设计的FD3-64航模涡喷发动机的设计，开创了小型发动机设计先河，用一个简单方法制作的放射式压气机，环型燃烧室，一个用简单方法制做出来的涡轮，达到了良好的效果。他的理念已被最新改进的各种新的设计所证实，并且都是以他的设计为基础进行的提炼。数字显示，许多爱好者根据他的著作理论，成功地将发动机用在了航模上。


涡轮喷气发动机材料为不锈钢为主，材料成本很低，如果从材料本身的价值来说，以广州为例，也就100元上下，但由于个人爱好者，有些可能无机床，氩弧焊的话，到外面加工的人力成本会贵过材料费。但也无妨。再就是如果有认识不锈钢加工厂的话，找到边角料足矣做一台涡轮,如果你想省事些，可以用涡轮增压器上的压气轮来代替木头的压气轮。。

2.涡轮容易加工吗,没专业设备如何做动平衡？

涡轮是由型号为301,2.5mm不锈板剪口弯成，用一个小电钻配小砂轮可以打磨出翼型即可，关键的动平衡测试，记住这一点很重要！！否则会导致发动机解体！！是用我们的大拇指与食指来感觉振动。灵敏度相当高。足以完成涡轮的动平衡调试。

3.散热与轴承问题
Bearings

The compressed air in the chamber passes down the bearing tube and exits both ends to provide cooling to the bearings. The bearings are simple ball races and they are oiled with oil mist supplied buy the pressure from the engine itself. Very low flows of oil are better than a constant flow as the drops can cause the ball to skid in the raceways. Turbine oil or thin machine oil can be used.
压缩空气将穿过轴套为轴承提供冷却，轴承为简单的滚珠轴承，用自身的压缩空气压油提供油雾润滑。可以用透平油，或低粘度的机械润滑油。
FD3-64的设计合理的利用压气机的空气，将温度控制在600度以下，从而保证各部件的强度。
在运行中我们要注意发动机的温度不能超高。


4.fd3-64能推多重的模型，国内造价要多少？


对于航模飞机来说，0.5的推重比完成各种特技动作都已够了，这台发动机的设计推力约3kg力，也就是说，你的航模总重达6kg在飞行中都没问题。
按fd3-64r材料本身来说不值钱，不锈钢在国内100元就买齐了，主要是加工费用问题，可能是的数倍。


5.（爱好者问得最多的问题）：根据国外的这些资料我能做出涡轮发动机来吗？？？

国外的这些资料 ，是国外的爱好者制作成功总结出来的，，作者通过总结数年来自己开发，研究涡轮发动机，对涡轮发动机的原理，涡轮发动机的自行设计的方法都 做了详细的介绍，尤其是制作过程，每一个部件的加工详细方法，与注意事项，如何控制加工精度等，都 一一描述，以确保用普通的机床，达到涡轮的制作要求。特别是一些动平衡的调试，用最简单的方法就能达到要求，。也就是说凡事爱好者能想到的问题，制作过程中会碰到的问题，这些资料都全面进行了讲解，并给出解决方法。


6,关于我网上提供的喷气制作光盘问题

有个别爱好者收到我的光盘后，可能对目前涡喷的发动机制作类型不太很了解，不知看那个目录为好，由于翻译成了中文，英文题目也成了中文，特此解答，碟的目录指引。《光碟中的《航模涡轮喷气发动机制作》与fd3-64制作过程，即为英国原著《gas turbine engine for model aircraft》一书，，《kj66制作蓝图与指导》即为涡轮发动机kj66的英文原版扫描手册，这是最主要的制作资料，以及德文版的全套AUTOCAD蓝图。剩下的内容，涡轮加工知识，涡轮相册，涡轮加工过程相册，涡喷机飞行片断，是为了制作fd3-64与kj66提高直观的参考。因为许多爱好者没见过真正的发动机，也不知材料与轴承的选型。所以收录资料上去是为了让大家更方便制作。同时也收录了上百种飞机模型的图纸供大家做喷气飞机用。




需要详细涡喷自制蓝图与加工手册书请点下面的图标！！
<喷气发动机制作大全>



以下问答摘自：（GTBA)英国喷气发动机制作协会

Starting the engine
启动发动机

All engines require a large volume of air to start them. Some like the AMT and JPX use scuba tanks. The home-built engines mostly are started with a fan held on the air intake. The fan can be a converted hairdryer fitted with a more powerful motor. The alternative is to use a high revving small electric motor onto a friction cup. The supplementary gas is lighted and the fan increases the revs . The liquid fuel is slowly fed in until the engine speed picks up and the engine self sustains. It can get hot when starting if too much fuel is fed in to quickly. With practice starting is simple and undramatic , there should be no flames visible either during starting or running.


Controlling the speed
控制速度

This is achieved by the use of a speed controller that controls the fuel pump motor. When bench testing it is more convenient to control the speed by a hand operated controller such as a minidrill speed controller rather than use a transmitter receiver and speed controller. When mounted in a plane a motor speed controller is used or if available a fully programmed ECU. Overspeed should be controlled by a combination of battery power and pump pressure so that whatever happens to the receiver or transmitter the supply of fuel is restricted.

Underspeed can be controlled via a pressure switch that stops the engine if pressure drops below a pre determined point.


What is a sensible rev limit?
转速控制

In the Kamps book there is full detail on how to calculate the critical speed for the shaft. The speed will depend on the material the shaft is made of and the thickness as well as the weight of the compressor and turbine and their positions. In practice engines with a 316 or 310 stainless steel turbine should have the revs restricted to about 75,000 rpm. Above this speed the material will expand and cause it to bind on the housing. The Kamps engine is limited to about 103,000rpm and the new Schreckling at 117,000rpm. The higher the revs the more need there is for the engine being well balanced.


How do I balance the engine?
如何做动平衡

Simple static balancing has proved to be adequate. The method in the Kamps book produces good results. He uses a tube that contains 2 new bearings and the shaft to be balanced. This is laid on a flat surface such as a piece of glass and is rocked to and fro until the heavy point reaches the bottom. This is marked and a little is ground away on the heavy side. When the shaft is balanced the compressor is balanced. Though this is from the factory the balance has in practice found not to be accurate enough. The compressor is removed and the turbine wheel is fitted and this is balanced . The blades can be thinned or the roots can be ground away slightly to reduce the weight.


How do I make the turbine wheel?
如何制作涡轮

The early wheels are made from sheet that is slit and twisted to the correct angle and profiled by hand minigrinder. Better wheels can be ground from thick discs. This is time consuming but will give better results particularly with Inconel. Cast Inconel wheels are becoming available now for those that do not feel they have the skill to make one.


Are the engines noisy?

If you stand close to a gas turbine you will find the noise level greater than a piston engine. However in the air the noise is dissipated so that it is much less obtrusive than a piston engine. Indeed if a piston engine and a turbine are flying together it is difficult to hear the turbine at all.


How do I weld stainless steel?
如何焊接不锈钢

This is not a skill everyone can acquire. Thin stainless can be spot-welded so this covers the combustion chamber. The NGV assembly will require TIG welding. TIG sets are expensive and it may be necessary to find a specialist welder used to welding stainless steel to do the welding for you.


What instrumentation will I need?

At the very least when testing you will need a vacuum gauge that can measure up to 1 bar and a temperature gauge that can measure up to 1000deg C. A kitchen scales will provide thrust measurements. A rev counter can be made from the design in the newsletter. It is helpful also to be able to measure the fuel pump pressure but this needs a scale up to 3 bar.


What thrust will I get?
推力是多大？

This depends on the design that you make. The detailed specification is set out in the pages for each design but you can expect to get between 5.3lbs and 16.6 lbs.


How much will it cost?
做涡喷的费用是多少？

This will depend on how able you are to get scraps from you local welders/machine shop! The Schreckling FD3 64 is very cheap to build and would cost probably no more than ￡100. The other designs that have turbochargers and cast wheels will be more expensive - perhaps ￡300
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